Plasma or serum production and removal of fluids under reduced pressure

ABSTRACT

In some embodiments, the present invention generally relates to the separation of blood within a device to form plasma or serum. In some embodiments, the present invention generally relates to the removal of fluids, such as blood, contained within a device. In one aspect, the present invention is generally directed to systems and methods for receiving blood from a subject and processing the blood to form plasma or serum. For example, a device may be applied to the skin of a subject to receive blood from the subject and pass the blood through a separation membrane, which separates the blood into plasma and a portion concentrated in blood cells. As another example, blood or plasma may be allowed to clot within the device and serum (the unclotted portion of the blood) may be withdrawn from the device. The device may contain, in some cases, a vacuum source such as a pre-packaged vacuum to facilitate receiving of blood and/or passage of the blood through the separation membrane to produce plasma or serum. In certain embodiments, plasma, serum, or other fluids may be removed from the device by inserting a needle into a portion of the device that has reduced pressure, expelling gas into the device through the needle, then receiving plasma, serum, or other fluids through the needle.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/456,505, filed Apr. 26, 2012, entitled “Plasma or Serum Productionand Removal of Fluids under Reduced Pressure,” by Haghgooie, et al.,which claims the benefit of U.S. Provisional Patent Application Ser. No.61/480,941, filed Apr. 29, 2011, entitled “Plasma or Serum Productionand Removal of Fluids under Reduced Pressure,” by Haghgooie, et al.; andof U.S. Provisional Patent Application Ser. No. 61/549,437, filed Oct.20, 2011, entitled “Systems and Methods for Collection and/orManipulation of Blood Spots or Other Bodily Fluids,” by Bernstein, etal. Each of these is incorporated herein by reference.

FIELD OF INVENTION

In some embodiments, the present invention generally relates to theseparation of blood within a device to form plasma or serum. In someembodiments, the present invention generally relates to the removal offluids, such as blood, contained within a device.

BACKGROUND

Plasma is the liquid component of blood in which blood cells arenormally suspended. Serum is that portion of plasma in which clottingfactors such as fibrinogens have been removed. Plasma (including serum)forms about 55% of the total volume of blood. It is mostly water (about92-93% by volume) and contains dissolved proteins, glucose, clottingfactors, mineral ions, hormones and carbon dioxide. While plasma may beprepared by spinning a tube of fresh blood containing an anti-coagulantin a centrifuge until the blood cells fall to the bottom of the tube,other techniques for producing plasma are still needed. Plasma or serummay be important, for instance, for testing or diagnostics, e.g., forinfections, diabetes (e.g., sugar), AIDS (e.g., HIV), cancer (e.g.,prostate-specific antigen), or other indications. In many cases, only arelatively small amount of plasma or serum is needed for testingpurposes; however, a much large volume of blood is often required forcentrifugation and/or processing.

SUMMARY OF THE INVENTION

In some embodiments, the present invention generally relates to theseparation of blood within a device to form plasma or serum. In someembodiments, the present invention generally relates to the removal offluids, such as blood, contained within a device. The subject matter ofthe present invention involves, in some cases, interrelated products,alternative solutions to a particular problem, and/or a plurality ofdifferent uses of one or more systems and/or articles.

In one aspect, the present invention is directed to a device forreceiving bodily fluid from the subject and processing the bodily fluidto form plasma or serum. The device may include an inlet forintroduction of a bodily fluid from the subject into the device, aseparation membrane in fluid communication with the inlet on a firstside of the membrane, a vacuum chamber having a pressure less thanambient pressure, and a seal that can be manipulated to control a fluidcommunication pathway between the vacuum chamber and a second side ofthe separation membrane. In another aspect, the vacuum chamber may be ingaseous communication with a second side of the membrane. In yet anotheraspect, the device may have an applicator region including an openingarranged to receive a fluid and a seal that can be manipulated tocontrol a fluid communication pathway between the vacuum chamber and asecond side of the separation membrane. In yet another aspect, thevacuum chamber may be in gaseous communication with a second side of theseparation membrane.

In one aspect, the device may have two membranes. The first membraneseparates the inlet from the storage chamber and is substantiallyimpermeable to cells. The second membrane is gas permeable but issubstantially liquid impermeable. In some embodiments, the secondmembrane separates the storage chamber from the vacuum chamber.

In one aspect, the device may contain an applicator region that includesan opening arranged to receive fluid from a subject.

In one aspect, the present invention is directed to a method ofproducing plasma or serum from blood. The method includes applying adevice to the skin of a subject and causing the device to receive nomore than about 5 ml of blood from the subject. The blood received fromthe subject is separated within the device to form plasma or serum. Inanother aspect, the method includes concentrating at least a portion ofthe blood cells in the blood received from the subject.

In one aspect, the method includes providing a device having a firstchamber containing a liquid and a second chamber having a pressure lessthan ambient pressure. The first chamber and the second chamber areseparated by a membrane. The method also includes inserting at least aportion of a needle into the first chamber, causing the needle to expela gas into the first chamber, wherein the gas does not cause the liquidto enter the second chamber, and receiving a portion of the liquid fromthe first chamber into the needle.

In another aspect, the present invention encompasses methods of makingone or more of the embodiments described herein, for example, a devicefor separating plasma or serum from blood. In still another aspect, thepresent invention encompasses methods of using one or more of theembodiments described herein, for example, a device for separatingplasma or serum from blood.

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures. In cases where the present specification and adocument incorporated by reference include conflicting and/orinconsistent disclosure, the present specification shall control. If twoor more documents incorporated by reference include conflicting and/orinconsistent disclosure with respect to each other, then the documenthaving the later effective date shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1 illustrates a device in accordance with one embodiment of theinvention, containing various membranes;

FIGS. 2A-2C illustrate the removal of a liquid from a device, inaccordance with certain embodiments of the invention;

FIG. 3 illustrates a device in one embodiment of the invention, having avacuum chamber;

FIG. 4 illustrates a device in another embodiment of the invention,having a vacuum chamber and a storage chamber;

FIG. 5 illustrates a device in yet another embodiment of the invention,having a flow controller;

FIG. 6 illustrates a device according to another embodiment of theinvention;

FIG. 7 illustrates yet another embodiment of the invention in which adevice is actuated by a reversibly deformable structure;

FIGS. 8A and 8B illustrate yet another embodiment of the invention, inwhich a device is actuated by a reversibly deformable structure, atdifferent stages of operation of the device;

FIGS. 9A-9C illustrate various devices according to various embodimentsof the invention; and

FIGS. 10A-10B illustrate certain membranes that can be used to at leastpartially confine liquids, in accordance with certain embodiments of theinvention.

DETAILED DESCRIPTION

In some embodiments, the present invention generally relates to theseparation of blood within a device to form plasma or serum. In someembodiments, the present invention generally relates to the removal offluids, such as blood, contained within a device. In one aspect, thepresent invention is generally directed to systems and methods forreceiving blood from a subject and processing the blood to form plasmaor serum. For example, a device may be applied to the skin of a subjectto receive blood from the subject and pass the blood through aseparation membrane, which separates the blood into plasma and a portionconcentrated in blood cells. As another example, blood or plasma may beallowed to clot within the device and serum (the unclotted portion ofthe blood) may be received from the device. The device may contain, insome cases, a vacuum source such as a pre-packaged vacuum to facilitatereceiving of blood and/or passage of the blood through the separationmembrane to produce plasma or serum. In certain embodiments, plasma,serum, or other fluids may be removed from the device by inserting aneedle into a portion of the device that has reduced pressure, expellinggas into the device through the needle, then withdrawing plasma, serum,or other fluids through the needle. In other embodiments, the fluidwithin the device may be accessed without a using needle via ventingmanually, automatically, or by using a machine. Thereafter, fluid may beejected, or it may be extracted using a syringe, pipette, etc.

Certain aspects of the invention are generally directed to separatingblood into plasma or serum, and a portion enriched in blood cells, forexample, under vacuum or reduced pressure. For example, a device, suchas a portable device, may include a vacuum chamber or other vacuumsource having a pressure less than atmospheric or ambient pressure. Thereduced pressure may be used to draw blood (or other suitable bodilyfluids) into the device and/or through a membrane, such as a separationmembrane. In some embodiments, the membrane is used to separate theblood into a first portion formed of plasma or serum, and a secondportion that is concentrated in blood cells.

In some cases, the device may be used to separate a relatively smallamount of blood into plasma or serum and a portion concentrated in bloodcells. For example, less than about 10 ml, less than about 5 ml, lessthan about 3 ml, less than about 2 ml, less than about 1.5 ml, less thanabout 1 ml, less than about 800 microliters, less than about 600microliters, less than about 500 microliters, less than about 400microliters, less than about 300 microliters, less than about 200microliters, less than about 100 microliters, less than about 80microliters, less than about 60 microliters, less than about 40microliters, less than about 20 microliters, less than about 10microliters, or less than about 1 microliter of blood may be receivedinto the device and separated within the device. The plasma or serum canthen be recovered from the device, for example, using a needle to removeat least a portion of the plasma or serum, and subjected to variousdiagnostics or testing protocols, for example, for the detection ofinfections, diabetes (e.g., sugar), AIDS (e.g., HIV), cancer (e.g.,prostate-specific antigen), or other indications. In some embodiments,the device may be relatively small, in contrast with machines (such asdialysis machines) that are typically used in plasmapheresis. Forexample, the device may be handheld or be applied to the skin of asubject, e.g., using an adhesive, as is discussed below. The device maybe self-contained in some embodiments, i.e., such that the device isable to function to withdraw blood (or other bodily fluids) from asubject and separate it to produce plasma or serum without requiringexternal connections such as an external source of vacuum, an externalsource of power, or the like. For instance, a vacuum source within thedevice, e.g., a vacuum chamber, may be used to draw blood across theseparation membrane to produce plasma or serum.

Furthermore, in certain embodiments, the device is able to effectivelyproduce a relatively small amount of plasma or serum without requiring arelatively large amount of blood and/or without requiring a centrifugeto produce plasma or serum from the received blood. In some cases, atleast about 30%, at least about 40%, at least about 50%, at least about60%, at least about 70%, at least about 80%, or at least about 90% ofthe plasma or serum produced by the device may be received from thedevice, e.g., for use in subsequent testing or diagnostics. In contrast,in many prior art techniques where a sample of plasma or serum isrequired, e.g., for diagnostics or testing purposes, a relatively largevolume of blood is received from a subject into a test tube (e.g.,having a volume of at least 2 ml, at least 4 ml, at least 6 ml, or atleast about 10 ml, such as in the Vacutainer™ (Becton, Dickinson andcompany) or Vacuette™ (Greiner Bio-One GmBH) systems), then the testtube is processed (for example, via centrifugation) to separate theblood from the plasma or serum. A portion of the plasma or serum is thenremoved from the test tube for diagnostics or testing purposes; however,the remainder of the plasma or serum within the test tube is not neededfor subsequent testing or diagnostics, and is essentially wasted.Additionally, in some embodiments, serum may be produced without use ofan anticoagulant within the device, although in other embodiments, thedevice may contain an anticoagulant to produce plasma. In someembodiments, the membrane and/or the storage chamber may contain ananticoagulant to produce plasma. Alternatively, if there is noanticoagulant present in the device, fluid that flows through aseparation membrane into the storage chamber is free of blood cells andwill ultimately clot in the storage chamber, thereby producing a liquidcomponent, also known as serum. This serum can be collected viaaspiration or other suitable method out of the storage chamber, leavingthe blood clots in the storage chamber. Thus, many embodiments describedherein may be used to produce plasma or serum, depending on the presenceor absence of anticoagulant.

In some cases, the device may include a fluid transporter that receivesfluid from a subject. The fluid transporter may include an applicatorregion where bodily fluids from the body accumulate, and a vacuum orreduced pressure may be used to withdraw the bodily fluids from theapplicator region into the device, e.g., into a vacuum source or astorage chamber. In some cases, the vacuum source may be larger than theapplicator region. Still other aspects of the present invention aredirected to kits involving such devices, methods of making such devices,methods of using such devices, and the like.

The fluid transporter may include an opening of any size and/or geometrythat is constructed to receive fluid into the device. For example, theopening may lie in a two-dimensional plane or the opening may include athree-dimensional cavity, hole, groove, slit, etc. In some embodiments,the fluid transporter may also include a flow activator, such as one ormore microneedles, arranged to cause fluid to be released from thesubject, e.g., by piercing the skin of a subject. In some embodiments,if fluid may partially or fully fill an enclosure surrounding a flowactivator, then the enclosure can define at least part of a fluidtransporter.

It should be noted that a flow activator need not be included with allembodiments as the device may not necessarily employ a mechanism forcausing fluid release from the subject. For instance, the device mayreceive fluid that has already been released due to another cause, suchas a cut or an abrasion, fluid release due to a separate and independentdevice, such as a separate lancet, an open fluid access such as during asurgical operation, and so on. Additionally, fluid may be introducedinto the device via urination, spitting, pouring fluid into the device,etc. If included, a flow activator may physically penetrate, pierce,and/or or abrade, chemically peel, corrode and/or irritate, releaseand/or produce electromagnetic, acoustic or other waves, other otherwiseoperate to cause fluid release from a subject. The flow activator mayinclude a moveable mechanism, e.g., to move a needle, or may not requiremovement to function. For example, the flow activator may include a jetinjector or a “hypospray” that delivers fluid under pressure to asubject, a pneumatic system that delivers and/or receives fluid, ahygroscopic agent that adsorbs or absorbs fluid, a reverse iontophoresissystem, a transducer that emits ultrasonic waves, or thermal,radiofrequency and/or laser energy, and so on, any of which need notnecessarily require movement of a flow activator to cause fluid releasefrom a subject.

One non-limiting example of such a device is now described withreference to FIG. 1; further details of this and other devices inaccordance with certain aspects of the present invention are alsodescribed in further detail below. In this example, device 10 is appliedto the skin 15 of a subject. The device in this figure isself-contained, i.e., such that the device is able to function towithdraw blood from a subject to produce plasma or serum withoutrequiring external connections such as an external source of vacuum, anexternal source of power, or the like. In other embodiments, however,the device need not be self-contained. Upon actuation of the deviceshown in FIG. 1, for example, remotely or by pressing button 20, flowactivators 25 are deployed into skin 15 of the subject. The flowactivators may include one or more needles or microneedles, or otherflow activators as discussed in detail below and/or in documentsincorporated herein by reference. Copies of these documents are alsoincluded at the end of this application. As shown in this figure, thedeployment of flow activators 25 into skin 15 of the subject may beaccomplished using a deployment actuator 28, or by other techniques suchas those described herein. The deployment actuator 28 may includesuitable components to deploy the flow activators 25, such as a button,a switch, a lever, a slider, a dial, a compression spring, a Bellevillespring, a servo, rotary or linear electric motor, and/or a pneumaticapparatus, or other suitable device.

A vacuum or a reduced pressure less than atmospheric or ambient pressuremay be used to facilitate the movement of blood 30 into the device, asfollows. The vacuum may be contained within device 10, for example,within vacuum chamber 35. Blood 30 on the skin 15 of the subject maybecome exposed to the vacuum or reduced pressure, which causes the bloodto enter device 10, e.g., through applicator region 40 into inlet 42 ofchannel 45, passing through membrane 50 towards storage chamber 33.Storage chamber 33 is located immediately on the other side of membrane50 in this particular example, and can be used to collect plasma orserum that is produced by drawing blood 30 through membrane 50. Membrane50 may be, for example, a separation membrane or a membrane that ispermeable to fluids but is substantially impermeable to cells.

When blood 30 reaches membrane 50, cells and other larger componentscannot pass therethrough, while fluids and smaller components are ableto pass through, thereby forming a plasma or serum within storagechamber 33 (or at least, a plasma-enriched fluid). Plasma or serumpresent within storage chamber 33 may be collected, e.g., for subsequentuse and/or analysis. In contrast, other components on the other side ofmembrane 50 may remain there, thereby forming a portion that isconcentrated or enriched in blood cells, i.e., the concentration ofblood cells in this portion may be higher than the initial concentrationof blood cells in the blood received from the subject.

In some embodiments, blood spots may be produced on a blood spotmembrane. In these cases, channel 45 may have a small volume relative tothe volume of a blood spot membrane which may be very porous and maycollect fluid. The blood spot membrane is used to collect fluid. Theblood spot membrane is not used to separate cells/plasma (as opposed tothe separation membranes discussed earlier). Fluid may fill the bloodspot membrane. A second hydrophobic membrane may be positioned on top ofthe collection membrane. Once fluid contacts the hydrophobic membrane,fluid collection ceases. The blood spot membrane may remain in thedevice to dry and is then removed from the device. Alternatively, theblood spot membrane may be removed from the device and dried outside ofthe device. In either case, vacuum is released prior to removal of theblood spot membrane.

The plasma or serum may be removed from storage chamber 33 using anysuitable technique. One non-limiting example is now described. However,it should be understood that other techniques may be used instead ofand/or in addition to the following, and that this technique may also beapplied to remove blood (or other bodily fluids) from a device such asdevice 10, whether separation of the blood into plasma or serum hasoccurred or not. Examples of other suitable techniques are disclosed inU.S. patent application Ser. No. 13/006,165, filed Jan. 13, 2011,entitled “Sampling Device Interfaces,” by Chickering, et al.,incorporated herein by reference in its entirety.

As one example, in certain cases, syringe 65 may be introduced throughseptum 60 to reach the storage chamber and/or a portion of the devicethat is in fluidic communication with storage chamber 33. However,syringe 65 may contain air, typically at atmospheric or ambientpressure, e.g., within needle 68 of syringe 65. Upon entry of needle 68through septum 60 such that needle 68 becomes fluidly communicative withstorage chamber 33 (which is typically at a vacuum or reduced pressure,as previously described), the air may cause the plasma, serum, or otherliquids to be moved or “blown” around the device, especially withinstorage chamber 33, and in some cases in a relatively uncontrolledfashion. In certain embodiments, to mitigate or reduce the effects ofthe introduction of additional air into storage chamber 33, vacuumchamber 35 may be separated from storage chamber 33 so that additionalair can be introduced into device 10 without causing the plasma, serum,or other liquids within storage chamber 33 to be moved around within thedevice, e.g., exiting storage chamber 33. As a non-limiting example, asshown in FIG. 1, a second membrane 75 separates vacuum chamber 35 fromstorage chamber 33. Second membrane 75 may be selected so as to allowpassage of gases but prevent the passage of liquids. For example, secondmembrane 75 can be a relatively hydrophobic membrane, or a membrane thathas a contact angle of at least 45° relative to an air/water interface.Other suitable membranes are discussed below. Accordingly, when air isintroduced into storage chamber 33, some of the air may pass acrosssecond membrane 75 into vacuum chamber 35; however, a liquid such asplasma, serum, or blood within storage chamber 33 is unable to pass intovacuum chamber 35, even under the influence of a driving force caused bythe introduction of air into storage chamber 33, and thus the liquidremains within storage chamber 33 after the pressures within device 10and needle 68, and/or the pressures within storage chamber 33 and vacuumchamber 35 have substantially equalized.

Accordingly, in certain aspects, the present invention is generallydirected to devices able to withdraw or extracting blood, interstitialfluid, or other bodily fluids from the skin of a subject, e.g., from theskin and/or from beneath the skin, or other mucosal surface, as well asmethods of use thereof. The received fluid may be any suitable bodilyfluid, such as interstitial fluid, other skin-associated material,mucosal material or fluid, whole blood, perspiration, saliva, plasma,serum, tears, lymph, urine, or any other bodily fluid, or combinationsthereof. Substances received from a subject can include solid orsemi-solid material such as skin, cells, or any other substance from theskin and/or beneath the skin of the subject. Substances that can bedelivered to a subject in accordance with some embodiments of theinvention include diagnostic substances, therapeutic substances such asdrugs, and the like. Various embodiments of the invention are describedbelow in the context of delivering or receiving a fluid, such as bloodor interstitial fluid, from the skin and/or beneath the skin. It is tobe understood that in all embodiments herein, regardless of the specificexemplary language used (e.g., withdrawing blood), the devices andmethods of other embodiments of the invention can be used for receivingany substance from the skin and/or from beneath the skin of the subject,and/or for delivering any substance to the subject, e.g., to the skinand/or a location beneath the skin of the subject.

In some cases, the device may contain a flow activator (for example, oneor more needles or microneedles). Examples of flow activators arediscussed in detail below. In some cases, the device may be used topierce the skin of the subject, and fluid can then be delivered toand/or received from the skin of the subject. Thus, it should beunderstood that in the discussions herein, references to withdrawing afluid “from the skin” includes embodiments in which a fluid is deliveredand/or received through the surface of the skin. For example, a fluidmay be delivered into or received from a layer of skin in oneembodiment, while in another embodiment a fluid may be delivered into orreceived from a region just below the skin of the subject, e.g., passingthrough the surface of the skin, as opposed to other routes ofadministration such as oral delivery. The subject is usually human,although non-human subjects may be used in certain instances, forinstance, other mammals such as a dog, a cat, a horse, a rabbit, a cow,a pig, a sheep, a goat, a rat (e.g., Rattus norvegicus), a mouse (e.g.,Mus musculus), a guinea pig, a hamster, a primate (e.g., a monkey, achimpanzee, a baboon, an ape, a gorilla, etc.), or the like.

As mentioned, in one aspect, blood received from a subject into a devicemay be separated within the device to form plasma or serum by passingthe blood, or at least a portion thereof, through a separation membraneor a membrane that is permeable to fluids but is substantiallyimpermeable to cells. The separation membrane can be any membrane ableto separate blood passing therethrough into a first portion (passingthrough the membrane) that is enriched in plasma or serum, and a secondportion (rejected by the membrane) concentrated in blood cells. In somecases, the separation membrane may have a separation effectivenessduring use (the separation effectiveness is the volume of plasma orserum that passes through the membrane relative to the starting volumeof whole blood) of at least about 5%, at least about 10%, at least about20%, at least about 40%, at least about 50%, at least about 55%, or atleast about 60%.

In one set of embodiments, the separation membrane is selected to have apore size smaller than the average or effective diameter of blood cellscontained within the blood, including red blood cells and white bloodcells. For instance, the pore size of the separation membrane may beless than about 30 micrometers, less than about 20 micrometers, lessthan about 10 micrometers, less than about 8 micrometers, less thanabout 6 micrometers, less than about 4 micrometers, less than about 3micrometers, less than about 2 micrometers, less than about 1.5micrometers, less than about 1 micrometer, less than about 0.5micrometers, etc. As specific non-limiting examples, the pore size maybe between about 0.5 micrometers and about 2 micrometers, or betweenabout 0.5 micrometers and about 1 micrometer. In addition, in someembodiments, the separation membrane may have a thickness of less thanabout 1 mm, less than about 750 micrometers, less than about 500micrometers, less than about 400 micrometers, less than about 350micrometers, less than about 300 micrometers, less than about 250micrometers, or less than about 200 micrometers.

The separation membrane may be formed out of any suitable material. Forexample, in some embodiments, the separation membrane may be formed outof a material that promotes thrombolysis or inhibits clot formation,such as a polyester, and/or the separation membrane may be formed and/orcoated with a biocompatible material, or at least a material that doesnot cause an active clotting response within the blood that theseparation membrane is exposed to. As specific non-limiting example, theseparation membrane can comprise or be formed from glass (e.g., glassfibers), and/or a polymer such as a polycarbonate, a polysulfone, apolyethersulfone, a polyarylethersulfone, a polyvinylpyrrolidone, apolypropylene, poly(2-methoxyethylacrylate), and/or a nitrocellulose,etc. In some embodiments, the membrane may include a copolymer such as agraft copolymer (for example,poly(propylene-graft-2-methoxyethylacrylate)), e.g., including any oneor more of these polymers and/or other suitable polymers. In some cases,the separation membrane may be asymmetric, e.g., having a differentseparation effectiveness depending on which way blood is passed acrossthe separation membrane to produce plasma. Many such separationmembranes may be readily obtained commercially, such as Pall VividPlasma Separation Membrane (GF, GX, and GR), as well as othercommercially available separation membranes.

During use, blood is moved towards the separation membrane using asuitable driving force to move the blood, for example, vacuum or otherreduced pressure as is discussed herein. A fluidic portion of the bloodis able to pass across the separation membrane to form plasma or serumon one side of the membrane, while other portions of the blood, e.g.,red and white blood cells, are rejected by the membrane and thus form aportion that becomes concentrated in blood cells. For example, serum maybe produced if no anticoagulant is present, in accordance with certainembodiments. Either or both portions of the blood may be collected,e.g., in an appropriate storage chamber, for further use, analysis,storage, etc., as is discussed herein.

As mentioned, in certain aspects, blood may be drawn from a subjectthrough an applicator region in the device. The applicator region may bepositioned to collect a bodily fluid on the skin of the subject that isreleased by a flow activator. Non-limiting examples of bodily fluidsinclude blood or interstitial fluid, as is discussed herein. The flowactivator may be applied to the skin, and optionally received from theskin, in order to cause the release of a bodily fluid to the applicatorregion of the device. For example, a flow activator may include one ormore needles or microneedles, a hygroscopic agent, etc., as is discussedherein. The flow activator can be centered with respect to theapplicator region in certain embodiments; in other embodiments, however,the flow activator is not centered within the applicator region, and insome embodiments, the flow activator may not necessarily enter theapplicator region. The applicator region may be any portion of thedevice that is sized and/or positioned to collect bodily fluids, and insome cases, the applicator region may have a relatively small sizeand/or volume.

In one set of embodiments, the volume of the applicator region isdefined relative to the opening of the applicator region, or the portionof the applicator region that is adjacent the skin of the subject whenthe device is applied to the skin of the subject. In some embodiments,the applicator region may be a recess or an indentation within the baseof the device, which can receive a fluid from the surface of the skin.The applicator region may have any suitable shape. For example, theapplicator region can be generally hemispherical, semi-oval,rectangular, irregular, etc. The volume of the applicator region can berelatively small in some embodiments. For example, the volume of theapplicator region may be less than about 10 ml, less than about 8 ml,less than about 5 ml, less than about 3 ml, less than about 2 ml, lessthan about 1.5 ml, less than about 1 ml, less than about 800microliters, less than about 600 microliters, less than about 500microliters, less than about 400 microliters, less than about 300microliters, less than about 200 microliters, or less than about 100microliters. Smaller volumes may be desirable, for example, to minimizethe amount of bodily fluid collected within the applicator region beforethe bodily fluid is able to be transported into the device, e.g.,through an inlet within the applicator region into the device.

In some instances, the applicator region may have a small volumerelative to a vacuum chamber contained within the device, e.g., inembodiments where a vacuum chamber is present in the device. The vacuumchamber may be a pre-packaged vacuum chamber as is discussed below.Without wishing to be bound by any theory, it is believed that arelatively small applicator region will result in less gas being drawninto the vacuum chamber upon the creation of a fluid communicationpathway between the vacuum source and the applicator region, e.g., as isdiscussed herein. This may allow more of the vacuum or reduced pressureto be able to draw more bodily fluid into the device. Thus, for example,the ratio between the volume of the applicator region to the volume ofthe vacuum chamber can be at least about 1:5, at least about 1:8, atleast about 1:10, at least about 1:12, at least about 1:15, etc.

The applicator region may also contain one or more inlets forintroduction of a bodily fluid from the subject into the device. Forexample, the inlet can be an inlet to a fluid communication pathway, achannel such as a microfluidic channel, or the like, which may extend tothe separation membrane, and/or to other portions of the device, e.g.,such that fluids entering the inlet are able to reach the separationmembrane, for example, under action of vacuum or reduced pressure beingused to move the fluid towards the separation membrane. See also U.S.Provisional Patent Application Ser. No. 61/480,977, entitled “Deliveringand/or Receiving Fluids,” by Gonzales-Zugasti, et al., filed on Apr. 29,2011, incorporated herein by reference in its entirety. Thus, the fluidcommunication pathway into the device may proceed to, for example, avacuum chamber, a storage or collection chamber, a separation membrane,a portion of the device containing a sensor, or the like, and/or one ormore of these. In some cases, a seal can be maniuplated to control thefluid communication pathway. In some cases, the seal may be manipulatedreversibly to open and close the fluid communication pathway. Forexample, the seal may be a valve that can be opened and closed manually,automatically, with a machine, etc. The seal may also be manipulatedirreversibly. For example, the seal may be punctured to open the fluidcommunication pathway and unable to re-seal. As non-limiting examples,the fluid communication pathway may include one or more microfluidicchannels as discussed herein; for example, the fluid communicationpathway may include one or more microfluidic channels having an averagecross-sectional diameter of between about 100 and about 700 micrometers,or between about 300 and about 500 micrometers. Other examples of fluidcommunication pathways are discussed herein, including other channelsand microfluidic channels.

The inlet may be positioned in any suitable location within theapplicator region, and one or more inlets may be present. In some cases,an inlet (or at least a portion thereof) may be positioned relativelyclose to the skin of the subject. For example, the inlet may bepositioned such that at least a portion of the inlet is positionedwithin about 5 micrometers, within about 3 micrometers, within about 1micrometer, within about 0.7 micrometers, within about 0.5 micrometers,or within about 0.3 micrometers of the skin or the opening of theapplicator region. As additional examples, the inlet (or at least aportion thereof) may be positioned to be within about 50%, within about30%, within about 20%, within about 10%, or within about 5% of the skinof the subject or the opening of the applicator region, where thepercentage may be taken relative to the distance between the opening ofthe applicator region and a point within the applicator regionperpendicularly furthest away from the opening.

In some aspects, a seal or other suitable apparatus may be used tocontrol a fluid communication pathway, for example, between the inletand a vacuum chamber and/or a storage chamber. For example, the seal maycomprise a valve or a pierceable surface that can be opened. However,enabling fluid communication between a vacuum source and a fluidtransporter opening need not necessarily involve the opening of a valveor other device that blocks flow, but instead may involve the creationof suitable vacuum to cause flow. In some embodiments, the seal isreversible, i.e., the seal may also be used to end the fluidcommunication pathway (for example, a valve that can be opened orclosed). In other embodiments, however, the seal is not reversible. Theseal can be activated using any suitable technique, e.g., automatically,remotely, manually, etc. In some cases, the seal may be self-activating,e.g., upon application to the skin of a subject. The seal may beactivated once, or multiple times in some cases. The seal may beactivated, for example, by pushing a button, flipping a switch, moving aslider, turning a dial, or the like. The subject, and/or another person,may activate the seal. In some embodiments, the seal, or at least aportion thereof, may also serve as an activator, as discussed herein.Other examples of seals are discussed U.S. Provisional PatentApplication Ser. No. 61/480,977, entitled “Delivering and/or ReceivingFluids,” by Gonzales-Zugasti, et al., filed on Apr. 29, 2011,incorporated herein by reference in its entirety.

Thus, according to certain aspects of the invention, a vacuum (orreduced pressure) may be used to facilitate the withdraw of blood (orother bodily fluids) from the subject, and/or for causing the bloodreceived from the subject to be separated within the device to formplasma or serum, and a portion concentrated in blood cells. Accordingly,in some aspects, the device may contain a suitable vacuum source. Insome cases, the vacuum source is one that is self-contained within thedevice, i.e., the device need not be connected to an external vacuumsource (e.g., a house vacuum) during use of the device to withdrawblood, interstitial fluid, or other bodily fluids from the skin and/orfrom beneath the skin. In certain embodiments, relatively small vacuumchambers may be used, e.g., so that the device may have a relativelysmall size. For example, the vacuum chamber may have a volume of lessthan about 25 ml, less than about 20 ml, less than about 15 ml, lessthan about 10 ml, less than about 5 ml, less than about 3 ml, less thanabout 2 ml, or less than about 1 ml.

For example, in one set of embodiments, the vacuum source may include avacuum chamber having a pressure less than atmospheric or ambientpressure before blood (or other fluid) is received into the device,i.e., the vacuum chamber is at a “negative pressure” (that is, negativerelative to atmospheric or ambient pressure) or a “vacuum pressure” (orjust having a “vacuum”). For example, the vacuum in the vacuum chambermay be at least about 50 mmHg, at least about 100 mmHg, at least about150 mmHg, at least about 200 mmHg, at least about 250 mmHg, at leastabout 300 mmHg, at least about 350 mmHg, at least about 400 mmHg, atleast about 450 mmHg, at least about 500 mmHg, at least 550 mmHg, atleast 600 mmHg, at least 650 mmHg, at least about 700 mmHg, or at leastabout 750 mmHg, i.e., below atmospheric or ambient pressure. Thus, thepressure within the vacuum is at a “reduced pressure” relative toatmospheric or ambient pressure, e.g., the vacuum chamber is a reducedpressure chamber. However, in other embodiments, it should be understoodthat other pressures may be used and/or that different methods may beused to produce other pressures (greater than or less than atmosphericor ambient pressure). As non-limiting examples, an external vacuum or amechanical device may be used as the vacuum source; various additionalexamples are discussed in detail herein.

As mentioned, the vacuum may be an external vacuum source, and/or thevacuum source may be self-contained within the device. For example,vacuums of at least about 50 mmHg, at least about 100 mmHg, at leastabout 150 mmHg, at least about 200 mmHg, at least about 250 mmHg, atleast about 300 mmHg, at least about 350 mmHg, at least about 400 mmHg,at least about 450 mmHg, at least about 500 mmHg, at least 550 mmHg, atleast 600 mmHg, at least 650 mmHg, at least about 700 mmHg, or at leastabout 750 mmHg may be applied to the skin. As used herein, “vacuum”refers to pressures that are below atmospheric or ambient pressure.

Any source of vacuum may be used. For example, the device may comprisean internal vacuum source, and/or be connectable to a vacuum source isexternal to the device, such as a vacuum pump or an external (line)vacuum source. In some cases, vacuum may be created manually, e.g., bymanipulating a syringe pump, a plunger, or the like, or the low pressuremay be created mechanically or automatically, e.g., using a piston pump,a syringe, a bulb, a Venturi tube, manual (mouth) suction, etc., or thelike.

As a specific, non-limiting example, in one embodiment, a device may beused to withdraw fluid using a vacuum without an external power and/or avacuum source. Examples of such devices that can use vacuum include skinpatches, strips, tapes, bandages, or the like. For instance, a skinpatch may be contacted with the skin of a subject, and a vacuum createdthrough a change in shape of a portion of the skin patch or other device(e.g., using a shape memory polymer), which may be used to deliver toand/or withdraw fluid from the skin and/or beneath the skin. As aspecific example, a shape memory polymer may be shaped to be flat at afirst temperature (e.g., room temperature) but curved at a secondtemperature (e.g., body temperature), and when applied to the skin, theshape memory polymer may alter from a flat shape to a curved shape,thereby creating a vacuum. As another example, a mechanical device maybe used to create the vacuum, For example, springs, coils, expandingfoam (e.g., from a compressed state), a shape memory polymer, shapememory metal, or the like may be stored in a compressed or wound stateupon application to a subject, then released (e.g., unwinding,uncompressing, etc.), to mechanically create the vacuum. In someembodiments, the device may be used to create a vacuum automatically,once activated, without any external control by a user.

Thus, in some cases, the device is “pre-packaged” with a suitable vacuumsource (e.g., a pre-evacuated vacuum chamber); for instance, in oneembodiment, the device may be applied to the skin and activated in somefashion to create and/or access the vacuum source. In yet anotherexample, a chemical reaction may be used to create a vacuum, e.g., areaction in which a gas is produced, which can be harnessed to providethe mechanical force to create a vacuum. In still another example, acomponent of the device may be able to create a vacuum in the absence ofmechanical force. In another example, the device may include aself-contained vacuum actuator, for example, chemical reactants, adeformable structure, a spring, a piston, etc.

In one set of embodiments, the device may be able to create a pressuredifferential (e.g. a vacuum). For example, the device may contain apressure differential chamber, such as a vacuum chamber or a pressurizedchamber, that can be used to create a pressure differential. Thepressure differential may be created by a pressure regulator. As usedhere, “pressure regulator” is a pressure controller component or systemable to create a pressure differential between two or more locations.The pressure differential should be at least sufficient to urge or movefluid or other material in accordance with various embodiments of theinvention as discussed herein, and the absolute pressures at the two ormore locations are not important so long as their differential isappropriate, and their absolute values are reasonable for the purposesdiscussed herein. For example, the pressure regulator may produce apressure higher than atmospheric or ambient pressure in one location,relative to a lower pressure at another location (atmospheric or ambientpressure or some other pressure), where the differential between thepressures is sufficient to urge or move fluid in accordance with theinvention. In another example, the regulator or controller will involvea pressure lower than atmospheric or ambient pressure (a vacuum) in onelocation, and a higher pressure at another location(s) (atmospheric orambient pressure or a different pressure) where the differential betweenthe pressures is sufficient to urge or move fluid in accordance with theinvention. Wherever “vacuum” or “pressure” is used herein, it should beunderstood that the opposite can be implemented as well, as would beunderstood by those of ordinary skill in the art, i.e., a vacuum chambercan be replaced in many instances with a pressure chamber, for creatinga pressure differential suitable for urging the movement of fluid orother material.

The pressure regulator may be an external source of vacuum (e.g. a lab,clinic, hospital, etc., house vacuum line or external vacuum pump), amechanical device, a vacuum chamber, pre-packaged vacuum chamber, apressurized chamber, or the like. In some cases, vacuum may be createdmanually, e.g., by manipulating a syringe pump, a plunger, or the like,or the low pressure may be created mechanically or automatically, e.g.,using a piston pump, a syringe, a bulb, a Venturi tube, manual (mouth)suction, etc., or the like. Vacuum chambers can be used in someembodiments, where the device contains, e.g., regions in which a vacuumexits or can be created (e.g. a variable volume chamber, a change involume of which will affect vacuum or pressure). A vacuum chamber caninclude pre-evacuated (i.e., pre-packaged) chambers or regions, and/orself-contained actuators.

A “self-contained” vacuum (or pressure) regulator means one that isassociated with (e.g., on or within) the device, e.g. one that definesan integral part of the device, or is a separate component constructedand arranged to be specifically connectable to the particular device toform a pressure differential (i.e., not a connection to an externalsource of vacuum such as a hospital's, clinic's, or lab's house vacuumline, or a vacuum pump suitable for general use). In some embodiments,the self-contained vacuum source may be actuated in some fashion tocreate a vacuum within the device. For instance, the self-containedvacuum source may include a piston, a syringe, a mechanical device suchas a vacuum pump able to create a vacuum within the device, and/orchemicals or other reactants that can react to increase or decreasepressure which, with the assistance of mechanical or other means drivenby the reaction, can form a pressure differential associated with apressure regulator. Chemical reaction can also drive mechanicalactuation with or without a change in pressure based on the chemicalreaction itself. A self-contained vacuum source can also include anexpandable foam, a shape memory material, or the like.

One category of self-contained vacuum or pressure regulators of theinvention includes self-contained assisted regulators. These areregulators that, upon actuation (e.g., the push of a button, orautomatic actuation upon, e.g., removal from a package or urging adevice against the skin), a vacuum or pressure associated with thedevice is formed where the force that pressurizes or evacuates a chamberis not the same as the actuation force. Examples of self-containedassisted regulators include chambers evacuated by expansion driven by aspring triggered by actuation, release of a shape-memory material orexpandable material upon actuation, initiation of a chemical reactionupon actuation, or the like.

Another category of self-contained vacuum or pressure regulators of theinvention are devices that are not necessarily pre-packaged withpressure or vacuum, but which can be pressurized or evacuated, e.g. by asubject, health care professional at a hospital or clinic prior to use,e.g. by connecting a chamber of the device to a source of vacuum orpressure. For example, the subject, or another person, may actuate thedevice to create a pressure or vacuum within the device, for example,immediately prior to use of the device.

The vacuum or pressure regulator may be a “pre-packaged” pressure orvacuum chamber in the device when used (i.e., the device can be providedready for use by a subject or practitioner with an evacuated region onor in the device, without the need for any actuation to form the initialvacuum). A pre-packaged pressure or vacuum chamber regulator can, e.g.,be a region evacuated (relative to atmospheric or ambient pressure) uponmanufacture and/or at some point prior to the point at which it is usedby a subject or practitioner. For example, a chamber is evacuated uponmanufacture, or after manufacture but before delivery of the device tothe user, e.g. the clinician or subject. For instance, in someembodiments, the device contains a vacuum chamber having a vacuum of atleast about 50 mmHg, at least about 100 mmHg, at least about 150 mmHg,at least about 200 mmHg, at least about 250 mmHg, at least about 300mmHg, at least about 350 mmHg, at least about 400 mmHg, at least about450 mmHg, at least about 500 mmHg, at least about 550 mmHg, at leastabout 600 mmHg, at least about 650 mmHg, at least about 700 mmHg, or atleast about 750 mmHg below atmospheric or ambient pressure.

In one set of embodiments, a device of the present invention may nothave an external power and/or a vacuum source. In some cases, the deviceis “pre-loaded” with a suitable vacuum source; for instance, in oneembodiment, the device may be applied to the skin and activated in somefashion to create and/or access the vacuum source. As one example, adevice of the present invention may be contacted with the skin of asubject, and a vacuum created through a change in shape of a portion ofthe device (e.g., using a shape memory polymer), or the device maycontain one or more sealed, self-contained vacuum chambers, where a sealis punctured in some manner to create a vacuum. For instance, uponpuncturing the seal, a vacuum chamber may be in fluidic communicationwith one or more needles, and the reduced pressure can be used to movethe skin towards the device, withdraw fluid from the skin and/or beneaththe skin, or the like.

As another example, a shape memory polymer may be shaped to be flat at afirst temperature (e.g., room temperature) but curved at a secondtemperature (e.g., body temperature), and when applied to the skin, theshape memory polymer may alter from a flat shape to a curved shape,thereby creating a vacuum. As yet another example, a mechanical devicemay be used to create the vacuum, For example, springs, coils, expandingfoam (e.g., from a compressed state), a shape memory polymer, shapememory metal, or the like may be stored in a compressed or woundreleased upon application to a subject, then released (e.g., unwinding,uncompressing, etc.), to mechanically create the vacuum. Non-limitingexamples of shape-memory polymers and metals include Nitinol,compositions of oligo(epsilon-caprolactone)diol and crystallizableoligo(rho-dioxanone)diol, or compositions ofoligo(epsilon-caprolactone)dimethacrylate and n-butyl acrylate.

In yet another example, a chemical reaction may be used to create avacuum, e.g., a reaction in which a gas is produced, which can beharnessed to provide the mechanical force to create a vacuum. In someembodiments, the device may be used to create a vacuum automatically,once activated, without any external control by a user.

In one set of embodiments, the device contains a vacuum chamber that isalso used as a storage chamber to receive blood, interstitial fluid, orother fluid received from the skin and/or beneath the skin of thesubject into the device. For instance, blood received from a subjectthrough or via the fluid transporter may enter the vacuum chamber due toits negative pressure (i.e., because the chamber has an internalpressure less than atmospheric or ambient pressure) to produce plasma orserum, and the blood, serum and/or plasma may be optionally stored inthe device, e.g., within a storage or collection chamber, or within avacuum chamber for later use. A non-limiting example is illustrated inFIG. 3. In this figure, device 600 contains vacuum chamber 610, which isconnected to flow activator 620 (which may be, e.g., one or more needlesor microneedles). Upon activation of vacuum chamber 610 (e.g., usingactuator 660, as discussed herein), vacuum chamber 610 may be put intofluidic communication with flow activator 620. Flow activator 620 mayaccordingly cause negative pressure to be applied to the skin of thesubject, for instance, due to the internal pressure within vacuumchamber 610. Blood received from the skin and/or beneath the skin viaflow activator 620 may accordingly be drawn into the device and intovacuum chamber 610, e.g., through conduit 612. Upon entry into thedevice, the blood may be passed across a separation membrane or amembrane that is permeable to fluids but is substantially impermeable tocells.

In another set of embodiments, however, the device may include separatevacuum chambers and storage chambers (e.g., chambers to store fluid suchas blood, serum, or plasma from the skin and/or beneath the skin of thesubject). The vacuum chamber and storage chambers may be in fluidcommunication, and may have any suitable arrangement. In someembodiments, the vacuum from the vacuum chamber may be used, at least inpart, to withdraw fluid from the skin and/or beneath the skin, which isthen directed into a storage chamber, e.g., for later analysis or use,for example, as discussed below. As an example, blood may be receivedinto the device, flowing towards a vacuum chamber, but the blood (orother fluid) may be prevented from entering the vacuum chamber. Forinstance, in certain embodiments, a material permeable to gas but not toa liquid such as blood or interstitial fluid may be used. For example,the material may be a membrane such as a hydrophilic or hydrophobicmembrane having a suitable porosity, a porous structure, a porousceramic frit, a dissolvable interface (e.g., formed from a salt or apolymer, etc.), or the like.

One non-limiting example is illustrated in FIG. 4. In this figure,device 600 contains vacuum chamber 610 and storage chamber 615. Vacuumchamber 610 can be put in fluidic communication with storage chamber 615via conduit 612, which contains material 614. Material 614 may be anymaterial permeable to gas but not to a liquid in this example, e.g.,material 614 may be a membrane such as a hydrophilic membrane or ahydrophobic membrane that has a porosity that allows gas exchange tooccur but does not allow the passage of blood or interstitial fluid fromthe skin and/or beneath the skin of the subject. When device 600 isactuated using actuator 660, blood (or other fluid) flows through flowactivator 620 via conduit 661 into storage chamber 615 because of theinternal vacuum pressure from vacuum chamber 610, which is notcompletely impeded by material 614 since it is permeable to gases.However, because of material 614, blood (or other bodily fluid) isprevented from entering vacuum chamber 610, and instead remains instorage chamber 615, e.g., for later analysis or use.

The needle (or other flow activator) may be used for delivering toand/or receiving fluids or other materials from a subject, e.g., to orfrom the skin and/or beneath the skin. For example, in some cases, avacuum chamber having a reduced pressure or an internal pressure lessthan atmospheric or ambient pressure prior to receiving blood or otherbodily fluids (e.g., interstitial fluid) may be used to assist in thereceiving of the fluid from the skin after the needle (or other flowactivator) has penetrated the skin. The fluid received from the skinand/or beneath the skin may be collected in the vacuum chamber and/or ina storage chamber. The storage chamber may be separated from the vacuumchamber using a gas permeable membrane (e.g., one that is substantiallyimpermeable to blood or other bodily fluids), a hydrophobic membrane, ahydrophilic membrane, a porous structure, a dissolvable interface, orthe like, e.g., as is discussed herein.

In some embodiments, the flow of blood (or other fluid, e.g.,interstitial fluid) into the storage chamber may be controlled using aflow controller. The flow controller may be manually and/orautomatically controlled to control the flow of blood. The flowcontroller may activate or deactivate when a certain amount or volume offluid has entered the storage chamber in certain cases. For instance,the flow controller may stop blood flow after a predetermined amount orvolume of blood has entered the storage chamber, and/or the flowcontroller may be able to control the internal pressure of the storagechamber, e.g., to a specific level, such as a predetermined level.Examples of suitable flow controllers for the device include, but arenot limited to, a membrane, a valve, a dissolvable interface, a gate, orthe like.

One non-limiting example of a flow controller is now illustrated withreference to FIG. 5. In this example figure, device 600 includes avacuum chamber 610 and a storage chamber 615. Fluid entering device 600via flow activator 620 is prevented from entering storage chamber 615due to flow controller 645 present within conduit 611. However, undersuitable conditions, flow controller 645 may be opened, thereby allowingat least some fluid to enter storage chamber 615. In some cases, forinstance, storage chamber 615 also contains at least a partial vacuum,although this vacuum may be greater or less than the pressure withinchamber 610. In other embodiments, flow controller 645 may initially beopen, or be externally controllable (e.g., via an actuator), or thelike. In some cases, the flow controller may control the flow of fluidinto the device such that, after collection, at least some vacuum isstill present in the device.

Thus, in some cases, the device may be constructed and arranged toreproducibly obtain from the skin and/or from beneath the skin of thesubject a controlled amount of fluid, e.g., a controlled amount orvolume of blood or interstitial fluid. The amount of fluid reproduciblyobtained from the skin and/or beneath the skin of the subject may becontrolled, for example, using flow controllers, materials permeable togas but not to liquids, membranes, valves, pumps, gates, microfluidicsystems, or the like, as discussed herein. In particular, it should benoted that the volume of blood or other fluid obtained from the skinand/or beneath the skin of the subject need not be strictly a functionof the initial vacuum pressure or volume within the device. For example,a flow controller may initially be opened (e.g., manually,automatically, electronically, etc.) to allow fluid to begin enteringthe device; and when a predetermined condition is reached (e.g., when acertain volume or amount of blood or interstitial fluid has entered thedevice), the flow controller may be closed at that point, even if somevacuum remains within the device. In some cases, this control of fluidallows the amount of fluid reproducibly obtained from the skin and/orbeneath the skin of the subject to be controlled to a great extent. Forexample, in one set of embodiments, the amount of fluid received fromthe skin and/or beneath the skin of the subject may be controlled to beless than about 1 ml, may be less than about 300 microliters, less thanabout 200 microliters, less than about 100 microliters, less than about50 microliters, less than about 30 microliters, less than about 20microliters, less than about 10 microliters, less than about 5microliters, less than about 3 microliters, less than about 2microliters, less than about 1 microliter, etc.

In some embodiments, the device may be connected to an externalapparatus for determining at least a portion of the device, a fluid(e.g., plasma or serum) removed from the device, an analyte suspected ofbeing present within the fluid, or the like. For example, the device maybe connected to an external analytical apparatus, and fluid removed fromthe device for later analysis, or the fluid may be analyzed within thedevice in situ, e.g., by adding one or more reaction entities to thedevice, for instance, to a storage chamber, or to analytical chamberwithin the device. For example, in one embodiment, the externalapparatus may have a port or other suitable surface for mating with aport or other suitable surface on the device, and blood, interstitialfluid, or other fluid can be removed from the device using any suitabletechnique, e.g., using vacuum or pressure, etc. The blood or other fluidmay be removed by the external apparatus, and optionally, stored and/oranalyzed in some fashion. For example, in one set of embodiments, thedevice may include an exit port for removing a fluid from the device(e.g., blood). In some embodiments, fluid contained within a storagechamber in the device may be removed from the device, and stored forlater use or analyzed outside of the device. In some cases, the exitport may be separate from the flow activator. An example is shown withexit port 670 and flow activator 620 in device 600 in FIG. 6. As shownin this figure, the exit port can be in fluidic communication withvacuum chamber 610. As another example, an exit port can be in fluidiccommunication with a vacuum chamber, which can also serve as a fluidreservoir in some cases. Other methods for removing blood, interstitialfluid, or other fluids from the device include, but are not limited to,removal using a vacuum line, a pipette, extraction through a septuminstead of an exit port, or the like. In some cases, the device may alsobe positioned in a centrifuge and subjected to various g forces (e.g.,to a centripetal force of at least 50 g), e.g., to cause at separationof cells or other substances within a fluid within the device to occur.One aspect of the invention is generally directed to methods forwithdrawing liquid from a device. The liquid may be blood, plasma,serum, or other fluids contained within the device. For example, in oneset of embodiments, a liquid such as plasma or serum may be removed froma storage chamber within the device. The storage chamber may also be avacuum chamber, or the storage chamber may be one that is at leastpartially separated from a vacuum chamber, for example, by a membrane.In addition, in some cases, a seal can be used to control a fluidcommunication pathway between the vacuum chamber and the storagechamber. In one set of embodiments, a storage chamber containing a fluidsuch as plasma or serum can be in gaseous communication with the vacuumchamber, e.g., such that the pressures within the storage chamber andthe vacuum chamber are substantially equal. However, the storage chamberand the vacuum chamber may not necessarily be in liquid communicationwith each other, for example, due to the presence of a membrane or otherstructure (e.g., a retaining wall) separating the storage chamber andthe vacuum chamber. If a membrane is used, the membrane can be, forexample, a hydrophobic membrane, or a membrane that is gas permeable butis substantially liquid impermeable.

To remove a fluid such as plasma or serum from the storage chamber, aneedle (e.g., of a syringe) may be inserted through a septum or otherpierceable material into the storage chamber, and/or to a portion of thedevice in fluidic communication with the storage chamber, e.g., suchthat the needle can access a liquid within the storage chamber or influidic communication with the storage chamber. The needle may beinserted, e.g., manually or automatically by an external apparatus,e.g., as is described herein. The septum or other pierceable materialmay comprise, for example, silicone or another suitable material, and insome cases, can be re-sealed once the needle has been removed, e.g., tomaintain the pressure within the device at a vacuum or reduced pressure.

However, the needle can contain some residual gas (typically air). Thus,upon insertion of the needle into the device, the gas from within theneedle may be introduced into the device, e.g., into the storagechamber. In some cases, the pressure of the gas within the needle isgreater than the pressure within the storage chamber, and the differencein pressure and the introduction of gas from the needle into the storagechamber may cause liquids within the storage chamber to move within thedevice. In some cases, the movement or flow of the liquids may berelatively uncontrolled within the device as the pressures within thedevice re-equalize due to the presence of the needle and the gasescontained therein.

Accordingly, in certain embodiments of the invention, one or moremembranes may be used to at least partially confine liquids within thestorage chamber such that the liquids do not move around the device,and/or are permitted to only move around certain portions of the device,while gases may be permitted to move within the device, e.g., tosubstantially equalize pressures within the device. For example, one ormore membranes or other suitable structures may be used to contain aliquid, such as plasma or serum, within the storage chamber.

If membranes are used, the membranes may be selected, for example, to besubstantially hydrophobic, and/or such that the membrane is gaspermeable but is substantially liquid impermeable. For example, themembrane may be selected to have a pore size that allows gaseousexchange to occur but is too small to allow substantial liquidpenetration to occur (e.g., due to capillary action). For example, themembrane may have a pore size of less than about 1000 micrometers, lessthan about 500 micrometers, less than about 300 micrometers, less thanabout 100 micrometers, less than about 50 micrometers, less than about30 micrometers, less than about 10 micrometers, less than about 5micrometers, less than about 3 micrometers, or less than about 1micrometer. In some embodiments, the membrane may be chosen to besubstantially hydrophobic, e.g., if the liquid contained within thestorage chamber is aqueous or hydrophilic. For example, the hydrophobicmembrane may exhibit a water/air contact angle of at least about 45° orat least about 90°.

The membrane may be formed out of any suitable material. For example,the membrane may include a polymer such as a copolymer. In someembodiments, the membrane may include one or more polymers such as apolyamide, a polypropylene, a polyvinyl chloride, a polyvinylacetate, anylon, a polyvinylidene fluoride (PVDF), a polytetrafluoroethylene(PTFE), acrylic, unsaturated polyester (UPE), or the like. Many suchpolymeric membranes may be readily obtained commercially, such asMillipore Fluoropore PTFE, Sterlitech NY125P, Pall Versapor (e.g., 450Ror 800R), Millipore SureVent DVSP, Millipore SureVent DOHP, MilliporeSureVent UPHP, or any other suitable polymeric membrane.

In certain instances, the membrane may be chosen to have an air flowrate of at least about 0.25 liter/(min cm² psi), and in some cases, atleast about 0.275 liter/(min cm² psi), at least about 0.3 liter/(min cm²psi), at least about 0.4 liter/(min cm² psi), at least about 0.5liter/(min cm² psi), at least about 0.6 liter/(min cm² psi), at leastabout 0.7 liter/(min cm² psi), at least about 0.8 liter/(min cm² psi),at least about 0.9 liter/(min cm² psi), at least about 1 liter/(min cm²psi), at least about 1.1 liter/(min cm² psi), at least about 1.2liter/(min cm² psi), at least about 1.3 liter/(min cm² psi), or at leastabout 1.4 liter/(min cm² psi). (1 psi is about 7 kPa.) Higher air flowrates may be desirable in some embodiments. In addition, in some cases,a membrane having a relatively high bubble point is desired, e.g., abubble point of at least about 5 psi, at least about 10 psi, or at leastabout 15 psi as measured for either water or blood.

In some cases, the membrane may be used to form one or more surfacesdefining the chamber for at least partially confining the liquid. Forinstance, referring to FIG. 10, in FIG. 10A, the top surface 205 ofchamber 202 is formed from such membranes, and when liquid 212 enterschamber 202 (e.g., from below), air (or other gases) can leave throughthe top surface, as is indicated by arrows 210. However, in FIG. 10B,all of the surfaces 205, 207 of chamber 202 are formed from suchmembranes, thereby allowing air (or other gases) to leave from any orall of these surfaces, as indicated by arrows 210. This may beimportant, for example, in configurations where the device is tilted orheld at an angle; even if liquid covers some portions of the chambersurface, there will be at least one surface formed from such membranesthrough which air or other gases are able to leave. Specific examples ofdevices with such configurations may be seen in U.S. and internationalpatent applications, each entitled “Methods and Devices for WithdrawingFluids from a Subject Using Reduced Pressure,” each filed on even dateherewith, each of which is incorporated herein by reference in itsentirety. In addition, it should be noted that although FIG. 10illustrates chambers having cylindrical configurations, this is by wayof example only, and in other embodiments, other chamber configurationsmay be used, e.g., rectangular, cubical, spherical, etc.

One non-limiting example of such a configuration is now described withreference to FIG. 2. In FIG. 2A, device 10 includes a storage chamber 33containing a liquid therein 31 to be removed, for example, blood,plasma, serum, interstitial fluid, or the like. Optionally, membrane 50may be present, which prevents liquid 31 from exiting storage chamber 33through channel 45. Channel 45 may be, for example, a channel throughwhich liquid 31 initially entered into storage chamber 33. In otherembodiments, other suitable systems may be used to prevent liquid 31from exiting storage chamber 33 through channel 45, for example, a valvesuch as a check valve or a flap valve, a gate, a pump, etc., may beused, such as described herein. Also shown in this figure is vacuumchamber 70, which may be in gaseous communication with storage chamber33, e.g., via membrane 75. Due to the presence of membrane 75, gases areable to pass between vacuum chamber 70 and storage chamber 33, althoughliquids such as liquid 31 are not able to enter vacuum chamber 70.

FIG. 2A also shows needle 68, which may be used to withdraw liquid 31from storage chamber 33. Needle 68 is to be inserted into device 10through septum 60 into storage chamber 33 and/or into a portion ofdevice 10 that is in fluidic or liquid communication with the liquidwithin storage chamber 33, as is shown in this figure. However, needle68 may contain a gas, typically air, which may be at atmospheric orambient pressure. This pressure may be greater than the pressure withinstorage chamber 33. Accordingly, once needle 68 is inserted into septum60, the gas within needle 68 is able to leave needle 68 and enterstorage chamber 33. Depending on the difference in pressure, the gas insome embodiments may leave needle 68 relatively violently or in anuncontrolled fashion, thereby “blowing around” liquid 31 within storagechamber 33, as is shown representatively in FIG. 2B. However, due to thepresence of membrane 75 and/or membrane 50, liquid 31 within storagechamber 33 is unable to leave the storage chamber, while gases are ableto leave, e.g., entering vacuum chamber 70, until the pressures withinneedle 68, storage chamber 33, and vacuum chamber 70 have substantiallyequalized, so that liquid 31 no longer is moved or “blown around” due toany pressure imbalances within the device. Liquid 31 can then be drawninto needle 68 to be removed from device 10, as is shown in FIG. 2C.

In certain aspects, the device includes a fluid transporter able towithdraw fluid from the skin and/or beneath the skin of the subject intothe device. As used herein, “fluid transporter” is any component orcombination of components that facilitates movement of a fluid from oneportion of the device to another, and/or from the device to the skin ofthe subject or vice versa. For example, at or near the skin, a fluidtransporter can be or include a hollow needle or a solid needle, orother flow activator, and/or a region (applicator region) into whichblood or other fluid is introduced. The flow activator may include amoveable mechanism, e.g., to move a needle, or may not require movementto function. For example, the flow activator may include a jet injectoror a “hypospray” that delivers fluid under pressure to a subject, apneumatic system that delivers and/or receives fluid, a hygroscopicagent that adsorbs or absorbs fluid, a reverse iontophoresis system, atransducer that emits ultrasonic waves, or thermal, radiofrequencyand/or laser energy, and so on, any of which need not necessarilyrequire movement of a flow activator to cause fluid release from asubject. If a solid needle is used, and fluid migrates along the needledue to surface forces (e.g., capillary action), then the solid needlecan be at least a part of a fluid transporter. If fluid (e.g. blood orinterstitial fluid) partially or fully fills an enclosure surrounding aneedle after puncture of skin (whether the needle is or is not retractedfrom the skin after puncture), then the enclosure can define a fluidtransporter. For example, the fluid transporter may include anapplicator region such as is described herein (with or without a needleor other flow activator therein). Other components including partiallyor fully enclosed channels, microfluidic channels, tubes, wickingmembers, vacuum containers, etc. can be fluid transporters.

The fluid may be received from and/or through the skin of a subject (orother mucosal surface). The fluid transporter may be, for example, oneor more needles and/or microneedles, a hygroscopic agent, a cutter orother piercing element, an electrically-assisted system, or the like,e.g., as discussed in detail herein. If needles or microneedles areused, they may be solid or hollow, i.e., blood, interstitial fluid, orother fluid may travel in and/or around the needles or microneedles intothe device. In some cases, the needles or microneedles may also beremoved from the skin of the subject, e.g., after insertion into theskin, for example, to increase the flow of blood or other fluids fromthe skin and/or beneath the skin of the subject. For example, one ormore needles or microneedles may be inserted into the skin and removed,and then a pressure gradient or a vacuum may be applied to the skin towithdraw a fluid, such as blood or interstitial fluid. In one set ofembodiments, the flow activator includes solid needles that are removedfrom the skin and a cup or channel may be used to direct the flow ofblood or other bodily fluids.

Non-limiting examples of flow activators include one or more needlesand/or microneedles, a hygroscopic agent, a cutter or other piercingelement, an electrically-assisted system, or any other systems asdescribed herein. Additional examples of such techniques are describedherein and/or in the applications incorporated herein. It is to beunderstood that, generally, fluids may be received in a variety of ways,and various systems and methods for receiving fluid from the skin and/orbeneath the skin are discussed below and/or in the applicationsincorporated herein. In one set of embodiments, techniques for piercingor altering the surface of the skin to transport a fluid are discussed,for example, using a needle such as a hypodermic needle or one or moremicroneedles, chemicals applied to the skin (e.g., penetrationenhancers), jet injectors or other techniques such as those discussedbelow.

As an example, in one embodiment, a needle such as a hypodermic needlecan be used to withdraw fluid to or from the skin and/or beneath theskin. Hypodermic needles are well-known to those of ordinary skill inthe art, and can be obtained commercially with a range of needle gauges.For example, the needle may be in the 20-30 gauge range, or the needlemay be 32 gauge, 33 gauge, 34 gauge, etc.

If needles are present, there may be one or more needles, the needlesmay be of any suitable size and length, and the needles may each besolid or hollow. The needles may have any suitable cross-section (e.g.,perpendicular to the direction of penetration), for example, circular,square, oval, elliptical, rectangular, rounded rectangle, triangular,polygonal, hexagonal, irregular, etc. For example, the needle may have alength of less than about 5 mm, less than about 4 mm, less than about 3mm, less than about 2 mm, less than about 1 mm, less than about 800micrometers, less than 600 micrometers, less than 500 micrometers, lessthan 400 micrometers, less than about 300 micrometers, less than about200 micrometers, less than about 175 micrometers, less than about 150micrometers, less than about 125 micrometers, less than about 100micrometers, less than about 75 micrometers, less than about 50micrometers, less than about 10 micrometers, etc. The needle may alsohave a largest cross-sectional dimension of less than about 5 mm, lessthan about 4 mm, less than about 3 mm, less than about 2 mm, less thanabout 1 mm, less than about 800 micrometers, less than 600 micrometers,less than 500 micrometers, less than 400 micrometers, less than about300 micrometers, less than about 200 micrometers, less than about 175micrometers, less than about 150 micrometers, less than about 125micrometers, less than about 100 micrometers, less than about 75micrometers, less than about 50 micrometers, less than about 10micrometers, etc. For example, in one embodiment, the needle may have arectangular cross section having dimensions of 175 micrometers by 50micrometers. In one set of embodiments, the needle may have an aspectratio of length to largest cross-sectional dimension of at least about2:1, at least about 3:1, at least about 4:1, at least 5:1, at leastabout 7:1, at least about 10:1, at least about 15:1, at least about20:1, at least about 25:1, at least about 30:1, etc.

In one embodiment, the needle is a microneedle. Typically, a microneedlewill have an average cross-sectional dimension (e.g., diameter) of lessthan about a millimeter. It should be understood that references to“needle” or “microneedle” as discussed herein are by way of example andease of presentation only, and that in other embodiments, more than oneneedle and/or microneedle may be present in any of the descriptionsherein.

As an example, microneedles such as those disclosed in U.S. Pat. No.6,334,856, issued Jan. 1, 2002, entitled “Microneedle Devices andMethods of Manufacture and Use Thereof,” by Allen, et al., may be usedto withdraw fluids (or other materials) from a subject. The microneedlesmay be hollow or solid, and may be formed from any suitable material,e.g., metals, ceramics, semiconductors, organics, polymers, and/orcomposites. Examples include, but are not limited to, medical gradestainless steel, titanium, nickel, iron, gold, tin, chromium, copper,alloys of these or other metals, silicon, silicon dioxide, and polymers,including polymers of hydroxy acids such as lactic acid and glycolicacid polylactide, polyglycolide, polylactide-co-glycolide, andcopolymers with polyethylene glycol, polyanhydrides, polyorthoesters,polyurethanes, polybutyric acid, polyvaleric acid,polylactide-co-caprolactone, polycarbonate, polymethacrylic acid,polyethylenevinyl acetate, polytetrafluorethylene, polymethylmethacrylate, polyacrylic acid, or polyesters.

In some cases, more than one needle or microneedle may be used. Forexample, arrays of needles or microneedles may be used, and the needlesor microneedles may be arranged in the array in any suitableconfiguration, e.g., periodic, random, etc. In some cases, the array mayhave 3 or more, 4 or more, 5 or more, 6 or more, 10 or more, 15 or more,20 or more, 35 or more, 50 or more, 100 or more, or any other suitablenumber of needles or microneedles. In some embodiments, the device mayhave at least 3 but no more than 5 needles or microneedles (or otherflow activators), at least 6 but no more than 10 needles ormicroneedles, or at least 11 but no more than 20 needles ormicroneedles. Typically, a microneedle will have an averagecross-sectional dimension (e.g., diameter) of less than about a micron.

Those of ordinary skill in the art can arrange needles relative to theskin for these purposes including, in one embodiment, introducingneedles into the skin at an angle, relative to the skin's surface, otherthan 90°, i.e., to introduce a needle or needles into the skin in aslanting fashion so as to limit the depth of penetration. In anotherembodiment, however, the needles may enter the skin at approximately90°.

In some cases, the needles (or microneedles) may be present in an arrayselected such that the density of needles within the array is betweenabout 0.5 needles/mm² and about 10 needles/mm², and in some cases, thedensity may be between about 0.6 needles/mm² and about 5 needles/mm²,between about 0.8 needles/mm² and about 3 needles/mm², between about 1needles/mm² and about 2.5 needles/mm², or the like. In some cases, theneedles may be positioned within the array such that no two needles arecloser than about 1 mm, about 0.9 mm, about 0.8 mm, about 0.7 mm, about0.6 mm, about 0.5 mm, about 0.4 mm, about 0.3 mm, about 0.2 mm, about0.1 mm, about 0.05 mm, about 0.03 mm, about 0.01 mm, etc.

In another set of embodiments, the needles (or microneedles) may bechosen such that the area of the needles (determined by determining thearea of penetration or perforation on the surface of the skin of thesubject by the needles) allows for adequate flow of fluid to or from theskin and/or beneath the skin of the subject. The needles may be chosento have smaller or larger areas (or smaller or large diameters), so longas the area of contact for the needles to the skin is sufficient toallow adequate blood flow from the skin of the subject to the device.For example, in certain embodiments, the needles may be selected to havea combined skin-penetration area of at least about 500 nm², at leastabout 1,000 nm², at least about 3,000 nm², at least about 10,000 nm², atleast about 30,000 nm², at least about 100,000 nm², at least about300,000 nm², at least about 1 microns², at least about 3 microns², atleast about 10 microns², at least about 30 microns², at least about 100microns², at least about 300 microns², at least about 500 microns², atleast about 1,000 microns², at least about 2,000 microns², at leastabout 2,500 microns², at least about 3,000 microns², at least about5,000 microns², at least about 8,000 microns², at least about 10,000microns², at least about 35,000 microns², at least about 100,000microns², at least about 300,000 microns², at least about 500,000microns², at least about 800,000 microns², at least about 8,000,000microns², etc., depending on the application.

The needles or microneedles may have any suitable length, and the lengthmay be, in some cases, dependent on the application. For example,needles designed to only penetrate the epidermis may be shorter thanneedles designed to also penetrate the dermis, or to extend beneath thedermis or the skin. In certain embodiments, the needles or microneedlesmay have a maximum penetration into the skin of no more than about 3 mm,no more than about 2 mm, no more than about 1.75 mm, no more than about1.5 mm, no more than about 1.25 mm, no more than about 1 mm, no morethan about 900 microns, no more than about 800 microns, no more thanabout 750 microns, no more than about 600 microns, no more than about500 microns, no more than about 400 microns, no more than about 300microns, no more than about 200 microns, no more than about 175micrometers, no more than about 150 micrometers, no more than about 125micrometers, no more than about 100 micrometers, no more than about 75micrometers, no more than about 50 micrometers, etc. In certainembodiments, the needles or microneedles may be selected so as to have amaximum penetration into the skin of at least about 50 micrometers, atleast about 100 micrometers, at least about 300 micrometers, at leastabout 500 micrometers, at least about 1 mm, at least about 2 mm, atleast about 3 mm, etc.

In one set of embodiments, the needles (or microneedles) may be coated.For example, the needles may be coated with a substance that isdelivered when the needles are inserted into the skin. For instance, thecoating may comprise heparin, an anticoagulant, an anti-inflammatorycompound, an analgesic, an anti-histamine compound, etc. to assist withthe flow of blood from the skin of the subject, or the coating maycomprise a drug or other therapeutic agent such as those describedherein. The drug or other therapeutic agent may be one used forlocalized delivery (e.g., of or proximate the region to which the coatedneedles or microneedles are applied), and/or the drug or othertherapeutic agent may be one intended for systemic delivery within thesubject.

In one embodiment, the fluid is received manually, e.g., by manipulatinga plunger on a syringe. In another embodiment, the fluid can be receivedfrom the skin and/or beneath the skin mechanically or automatically,e.g., using a piston pump or the like. Fluid may also be received usingvacuums such as those discussed herein. For example, vacuum may beapplied to a conduit, such as a needle, in fluidic communication with abodily fluid in order to draw up at least a portion of the fluid fromthe skin. In yet another embodiment, fluid is received using capillaryaction (e.g., using a microfluidic channel or hypodermic needle having asuitably narrow inner diameter). In still another embodiment, pressuremay be applied to force fluid out of the needle.

In some embodiments, fluid may be received using a hygroscopic agentapplied to the surface of the skin or proximate the skin. For example, adevice as described herein may contain a hygroscopic agent. In somecases, pressure may be applied to drive the hygroscopic agent into theskin. Hygroscopic agents typically are able to attract water from thesurrounding environment, for instance, through absorption or adsorption.Non-limiting examples of hygroscopic agents include sugar, honey,glycerol, ethanol, methanol, sulfuric acid, methamphetamine, iodine,many chloride and hydroxide salts, and a variety of other substances.Other examples include, but are not limited to, zinc chloride, calciumchloride, potassium hydroxide, or sodium hydroxide. In some cases, asuitable hygroscopic agent may be chosen based on its physical orreactive properties, e.g., inertness or biocompatibility towards theskin of the subject, depending on the application.

In some embodiments, the device may comprise a cutter able to cut orpierce the surface of the skin. The cutter may comprise any mechanismable to create a path through which fluids may be received from the skinand/or beneath the skin. For example, the cutter may comprise ahypodermic needle, a blade (e.g., a knife blade, a serrated blade,etc.), a piercing element (e.g., a lancet or a solid or a hollowneedle), or the like, which can be applied to the skin to create asuitable conduit for the receiving of fluid from the skin and/or frombeneath the skin. In one embodiment, a cutter is used to create such apathway and removed, then fluid may be received via this pathway. Inanother embodiment, the cutter remains in place within the skin, andfluid may be received through a conduit within the cutter.

In some embodiments, fluid may be received using an electric charge. Forexample, reverse iontophoresis may be used. Without wishing to be boundby any theory, reverse iontophoresis uses a small electric current todrive charged and highly polar compounds across the skin. Since the skinis negatively charged at physiologic pH, it acts as a permselectivemembrane to cations, and the passage of counterions across the skininduces an electroosmotic solvent flow that may carry neutral moleculesin the anode-to-cathode direction. Components in the solvent flow may beanalyzed as described elsewhere herein. In some instances, a reverseiontophoresis apparatus may comprise an anode cell and a cathode cell,each in contact with the skin. The anode cell may be filled, forexample, with an aqueous buffer solution (i.e., aqueous Tris buffer)having a pH greater than 4 and an electrolyte (i.e. sodium chloride).The cathode cell can be filled with aqueous buffer. As one example, afirst electrode (e.g., an anode) can be inserted into the anode cell anda second electrode (e.g., a cathode) can be inserted in the cathodecell. In some embodiments, the electrodes are not in direct contact withthe skin.

A current may be applied to induce reverse iontophoresis, therebywithdrawing a fluid from the skin. The current applied may be, forexample, greater than 0.01 mA, greater than 0.3 mA, greater than 0.1 mA,greater than 0.3 mA, greater than 0.5 mA, or greater than 1 mA. Itshould be understood that currents outside these ranges may be used aswell. The current may be applied for a set period of time. For example,the current may be applied for greater than 30 seconds, greater than 1minute, greater than 5 minutes, greater than 30 minutes, greater than 1hour, greater than 2 hours, or greater than 5 hours. It should beunderstood that times outside these ranges may be used as well.

In one set of embodiments, the device (flow activator) may comprise anapparatus for ablating the skin. Without wishing to be bound by anytheory, it is believed that ablation comprises removing a microscopicpatch of stratum corneum (i.e., ablation forms a micropore), thusallowing access to bodily fluids. In some cases, thermal,radiofrequency, and/or laser energy may be used for ablation. In someinstances, thermal ablation may be applied using a heating element.Radiofrequency ablation may be carried out using a frequency and energycapable of heating water and/or tissue. A laser may also be used toirradiate a location on the skin to remove a portion. In someembodiments, the heat may be applied in pulses such that a steeptemperature gradient exists essentially perpendicular to the surface ofthe skin. For example, a temperature of at least 100° C., at least 200°C., at least 300° C., or at least 400° C. may be applied for less than 1second, less than 0.1 seconds, less than 0.01 seconds, less than 0.005seconds, or less than 0.001 seconds.

In some embodiments, the device may comprise a mechanism for taking asolid sample of tissue. For example, a solid tissue sample may beacquired by methods such as scraping the skin or cutting out a portion.Scraping may comprise a reciprocating action whereby an instrument isscraped along the surface of the skin in two or more directions.Scraping can also be accomplished by a rotating action, for exampleparallel to the surface of the skin and in one direction (i.e., with aroller drum) or parallel to the surface of the skin and in a circularmanner (i.e., with a drilling instrument). A cutting mechanism maycomprise a blade capable of making one or more incisions and a mechanismfor removing a portion of tissue (i.e., by suction or mechanicallypicking up) or may use a pincer mechanism for cutting out a portion oftissue. A cutting mechanism may also function by a coring action. Forexample, a hollow cylindrical device can be penetrated into the skinsuch that a cylindrical core of tissue may be removed. A solid samplemay be analyzed directly or may be liquefied prior to analysis.Liquefaction can comprise treatment with organic solvents, enzymaticsolutions, surfactants, etc.

In certain embodiments, the flow activator may be fastened on a supportstructure. In some cases, the support structure can bring the flowactivator to the skin, and in certain instances, insert the fluidtransport into the skin. For example, the flow activator can be movedmechanically, electrically (e.g., with the aid of a servo, which may becomputer-controlled), pneumatically, via a piston, a screw, a mechanicallinkage, or the like. In one set of embodiments, the support structurecan insert the flow activator into the skin at a speed of at least about0.1 cm/s, at least about 0.3 cm/s, about 1 cm/s, at least about 3 cm/s,at least about 10 cm/s, at least about 30 cm/s, at least about 1 m/s, atleast about 2 m/s, at least about 3 m/s, at least about 4 m/s, at leastabout 5 m/s, at least about 6 m/s, at least about 7 m/s, at least about8 m/s, at least about 9 m/s, at least about 10 m/s, at least about 12m/s, etc., at the point where the flow activator initially contacts theskin. Without wishing to be bound by any theory, it is believed thatrelatively faster insertion speeds may increase the ability of the flowactivator to penetrate the skin (without deforming the skin or causingthe skin to move in response), and/or decrease the amount of pain feltby the application of the flow activator to the skin. Any suitablemethod of controlling the penetration speed into the skin may be used,include those described herein.

Thus in some aspects, the device may include a support structure forapplication to the skin of the subject. The support structure may beused, as discussed herein, for applying the flow activator to thesurface of the skin of the subject, e.g., so that fluid may be receivedfrom the skin and/or beneath the skin of the subject. In some cases, thesupport structure may immobilize the flow activator such that the flowactivator cannot move relative to the support structure; in other cases,however, the flow activator may be able to move relative to the supportstructure. In one embodiment, as a non-limiting example, the flowactivator is immobilized relative to the support structure, and thesupport structure is positioned within the device such that applicationof the device to the skin causes at least a portion of the flowactivator to pierce the skin of the subject. In some cases, as discussedherein, the support structure includes a reversibly deformablestructure.

In one set of embodiments, the support structure, or a portion of thesupport structure, may move from a first position to a second position.For example, the first position may be one where the support structurehas immobilized relative thereto a flow activator that does not contactthe skin (e.g., the flow activator may be contained within a recess),while the second position may be one where the flow activator doescontact the skin, and in some cases, the flow activator may pierce theskin. The support structure may be moved using any suitable technique,e.g., manually, mechanically, electromagnetically, using a servomechanism, or the like. In one set of embodiments, for example, thesupport structure may be moved from a first position to a secondposition by pushing a button on the device, which causes the supportstructure to move (either directly, or indirectly, e.g., through amechanism linking the button with the support structure). Othermechanisms (e.g., dials, levers, sliders, etc., as discussed herein) maybe used in conjunction with or instead of a button. In another set ofembodiments, the support structure may be moved from a first position toa second position automatically, for example, upon activation by acomputer, upon remote activation, after a period of time has elapsed, orthe like. For example, in one embodiment, a servo connected to thesupport structure is activated electronically, moving the supportstructure from the first position to the second position.

In some cases, the support structure may also be moved from the secondposition to the first position. For example, after fluid has beenreceived from the skin and/or beneath the skin, e.g., using a flowactivator the support structure may be moved, which may move the flowactivator away from contact with the skin. The support structure may bemoved from the second position to the first position using any suitabletechnique, including those described above, and the technique for movingthe support structure from the second position to the first position maybe the same or different as that moving the support structure from thefirst position to the second position.

In one set of embodiments, the device may include a flexible concavemember or a reversibly deformable structure that is moveable between afirst configuration and a second configuration. For instance, the firstconfiguration may have a concave shape, such as a dome shape, and thesecond configuration may have a different shape, for example, a deformedshape (e.g., a “squashed dome”), a convex shape, an inverted concaveshape, or the like. The flexible concave member (or a reversiblydeformable structure) may be moved between the first configuration andthe second configuration manually, e.g., by pushing on the flexibleconcave member using a hand or a finger, and/or the flexible concavemember may be moved using an actuator such as is described herein. Insome cases, the flexible concave member may be able to spontaneouslyreturn from the second configuration back to the first configuration. Inother cases, however, the flexible concave member may not be able toreturn to the first configuration, for instance, in order to preventaccidental repeated uses of the flexible concave member. The flexibleconcave member, in some embodiments, may be a reversibly deformablestructure, although in other embodiments, it need not be.

The flexible concave member (or a reversibly deformable structure, insome embodiments) may be mechanically coupled to one or more needles(e.g., microneedles), or other flow activators such as those discussedherein. The needle may be directly immobilized on the flexible concavemember, or the needles can be mechanically coupled to the flexibleconcave member using bars, rods, levers, plates, springs, or othersuitable structures. The needle (or other flow activator), in someembodiments, is mechanically coupled to the flexible concave member suchthat the needle is in a first position when the flexible concave memberis in a first configuration and the needle is in a second position whenthe flexible concave member is in a second configuration.

In some cases, relatively high speeds and/or accelerations may beachieved, and/or insertion of the needle may occur in a relatively shortperiod of time, e.g., as is discussed herein. The first position and thesecond position, in some cases, may be separated by relatively smalldistances. For example, the first position and the second position maybe separated by a distance of less than about 10 mm, less than about 9mm, less than about 8 mm, less than about 7 mm, less than about 6 mm,less than about 5 mm, less than about 4 mm, less than about 3 mm, orless than about 2 mm, etc. However, even within such distances, incertain embodiments, high speeds and/or accelerations such as thosediscussed herein can be achieved.

During use, a device may be placed into contact with the skin of asubject such that a recess or other suitable applicator region isproximate or in contact with the skin. By moving the flexible concavemember (or reversibly deformable structure) between a firstconfiguration and a second configuration, because of the mechanicalcoupling, the flexible concave member is able to cause a needle (orother flow activator) to move to a second position within the recess orother applicator region and to contact or penetrate the skin of thesubject.

In some embodiments, the device may also include a retraction mechanismable to move the needle (or other flow activator) away from the skinafter the flexible concave member (or a reversibly deformable structure)reaches a second configuration. Retraction of the flexible concavemember may, in some embodiments, be caused by the flexible concavemember itself, e.g., spontaneously returning from the secondconfiguration back to the first configuration, and/or the device mayinclude a separate retraction mechanism, for example, a spring, anelastic member, a collapsible foam, or the like.

In some cases, the support structure may be able to draw skin towardsthe flow activator. For example, in one set of embodiments, the supportstructure may include a vacuum interface or region. The interface orregion may be connected with a vacuum source (external and/or internalto the device), and when a vacuum is applied, skin may be drawn towardsthe support structure, e.g., for contact with a flow activator, such asone or more needles or microneedles.

In some cases, the device includes an interface that is able to applyvacuum to the skin. The interface may be, for example, a suction cup ora circular bowl that is placed on the surface of the skin, and vacuumapplied to the interface to create a vacuum. In one set of embodiments,the interface is part of a support structure, as discussed herein. Theinterface may be formed from any suitable material, e.g., glass, rubber,polymers such as silicone, polyurethane, nitrile rubber, EPDM rubber,neoprene, or the like. In some cases, the seal between the interface andthe skin may be enhanced (e.g., reducing leakage), for instance, usingvacuum grease, petroleum jelly, a gel, or the like. In some cases, theinterface may be relatively small, for example, having a diameter ofless than about 5 cm, less than about 4 cm, less than about 3 cm, lessthan about 2 cm, less than about 1 cm, less than about 5 mm, less thanabout 4 mm, less than about 3 mm, less than about 2 mm, or less thanabout 1 mm. The interface may be circular, although other shapes arealso possible, for example, square, star-shaped (having 5, 6, 7, 8, 9,10, 11, etc. points), tear-drop, oval, rectangular, or the like.

In some cases, the support structure may be able to draw skin towardsthe flow activator. For example, in one set of embodiments, the supportstructure may include a vacuum interface. The interface may be connectedwith a vacuum source (external and/or internal to the device), and whena vacuum is applied, skin may be drawn towards the support structure,e.g., for contact with a flow activator, such as with one or moreneedles or microneedles. The interface may also be selected, in somecases, to keep the size of the contact region below a certain area,e.g., to minimize pain or discomfort to the subject, for aestheticreasons, or the like. The interface may be constructed out of anysuitable material, e.g., glass, plastic, or the like.

In one set of embodiments, the device includes a reversibly deformablestructure able to drive a flow activator or a substance transfercomponent into the skin, e.g., so that the flow activator can withdraw afluid from the skin and/or from beneath the skin of a subject. Thereversibly deformable structure may be a structure that can be deformedusing unaided force (e.g., by a human pushing the structure), or otherforces (e.g., electrically-applied forces, mechanical interactions orthe like), but is able to restore its original shape after the force isremoved or at least partially reduced. For example, the structure mayrestore its original shape spontaneously, or some action (e.g., heating)may be needed to restore the structure to its original shape.

The reversibly deformable structure may be formed out a suitable elasticmaterial, in some cases. For instance, the structure may be formed froma plastic, a polymer, a metal, etc. In one set of embodiments, thestructure may have a concave or convex shape. For instance, the edges ofthe structure may be put under compressive stress such that thestructure “bows” out to form a concave or convex shape. A person pushingagainst the concave or convex shape may deform the structure, but afterthe person stops pushing on the structure, the structure may be able toreturn to its original concave or convex shape, e.g., spontaneously orwith the aid of other forces as previously discussed. In some cases, thedevice may be bistable, i.e., having two different positions in whichthe device is stable.

An example of a reversibly deformable structure is now illustrated withrespect to FIG. 7, which schematically illustrates device 1100 in whicha flow activator comprising a substance transfer component is driven bya reversibly deformable structure. In FIG. 7, device 1100 includes ahousing 1102 defining a plurality of chambers and channels. In otherembodiments (not shown) a plurality of components that can be separablefrom and attachable to each other (e.g., modular components) cantogether define the device and together define a series of channels andcompartments necessary for device function. See, e.g., U.S. patentapplication Ser. No. 12/716,233, filed Mar. 2, 2010, entitled “Systemsand Methods for Creating and Using Suction Blisters or Other PooledRegions of Fluid within the Skin,” by Levinson, et al.; U.S. patentapplication Ser. No. 12/716,226, filed Mar. 2, 2010, entitled“Techniques and Devices Associated with Blood Sampling,” by Levinson, etal.; U.S. patent application Ser. No. 12/716,229, filed Mar. 2, 2010,entitled “Devices and Techniques Associated with Diagnostics, Therapies,and Other Applications, Including Skin-Associated Applications,” byBernstein, et al.; or U.S. Provisional Patent Application Ser. No.61/411,566, filed Nov. 9, 2010, entitled “Systems and Interfaces forBlood Sampling,” by David Brancazio, each incorporated herein byreference.

In the specific device illustrated, device 1100 includes a surface 1104for positioning the device proximate the skin of a subject during use.Where desired in certain embodiments, the device can include an adhesivelayer 1106 where the adhesive is selected to be suitable for retainingthe device in a relatively fixed position relative to the skin duringuse, but may allow for relatively easy removal of the device from theskin following use. Specific non-limiting examples of adhesives arediscussed below. The adhesive also can be selected to assist inmaintaining a vacuum within portions of the device proximate the skin aswill be understood.

In FIG. 7, device 1100 includes a substance transfer component 1108. Thesubstance transfer component may be, for example, a flow activatorand/or a skin insertion object as discussed herein. Specificnon-limiting examples include one or more needles or microneedles, e.g.,as shown in FIG. 7. The substance transfer component can be, asdescribed elsewhere herein and in other documents incorporated herein byreference, any of a variety of components able to withdraw a substancefrom the skin and/or from beneath the skin of a subject. For example,the substance transfer component may include one or more needles and/ormicroneedles, a hygroscopic agent, a cutter or other piercing element,an electrically-assisted system, or the like. In the specific deviceillustrated, substance transfer component 1108 defines an array ofmicroinsertion objects such as solid or hollow microneedles. In one setof embodiments, substance transfer component 1108 is selected to have aparticular size and profile for a particular use. For example, thesubstance transfer component may include an array of insertion ormicroinsertion objects which, in the device illustrated, emanate from abase 1110 which will be described further below.

In certain embodiments, a plurality of skin insertion objects definesubstance transfer component 1108 and are relatively small, and arerelatively completely driven into the skin. Examples of skin insertionobjects include needles or microneedles, e.g., as described in greaterdetail below. The skin insertion objects may be positioned to addressthe skin of the subject, each protruding from a base and defining alength from the base, and are able to be inserted into or through theskin to a depth essentially equal to their length but are prevented, bythe base, from inserting at a depth greater than their length. In someembodiments, the plurality of skin insertion objects have an averagelength (measured from the base) of no more than about 1,000 microns ormore than about 2,000 microns, although lengths can differ betweenindividual skin insertion objects. In one set of embodiments, the skininsertion objects are of relatively uniform length, together defining anaverage length and each differing from the average length by no morethan about 50%, about 40%, about 30%, about 10%, or about 5%, e.g.,relative to the average length. The average length of the skin insertionobjects, in other embodiments, are no more than about 1,500 microns, nomore than about 1,000 microns, no more than about 900 microns, no morethan about 800 microns, no more than about 750 microns, no more thanabout 600 microns, no more than about 500 microns, no more than about400 microns, or no more than about 350 microns. In some embodiments, atriggering mechanism as discussed herein is provided that is able tomove the skin insertion objects from a fully predeployed position to afully deployed position with a force sufficient to insert the pluralityof skin insertion object into or through the skin to an average depth ofat least about 50% the average length of the plurality of skin insertionobjects. In other embodiments, the triggering mechanism is able toinsert the plurality of skin insertion objects to an average depth of atleast about 55%, at least about 60%, at least about 65%, at least about70%, at least about 75%, at least about 80%, at least about 85%, atleast about 90%, at least about 92%, about 94%, about 96%, or about 98%of the average length of the plurality of skin insertion objects.

In the device illustrated, substance transfer component 1108 is mountedon a flexible structure 1112 which, as illustrated, is maintainedrelatively rigidly through various aspects of the device but whichmounts substance transfer component 1108 flexibly for up/down movementrelative to the skin. Flexible structure 1112 can be a membrane, asingle or multi-layer structure selected from various polymers or thelike to provide sufficient properties such as any combination offlexibility, elasticity, gas permeability or impermeability, fluidpermeability or impermeability, or the like for desired operation.Portions of flexible structure 1112, substance transfer component 1108,and other interior walls of the device define a region 1114 which allowsfor movement of substance transfer component 1108 relative to the skinfor receiving of a substance from the skin or beneath the skin, and,where a substance is received from the skin or from beneath the skin,region 1114 can serve as a reservoir for introduction of the substanceinto the device. Where a vacuum is used to withdraw a substance from thesubject (e.g., as in the embodiment illustrated in FIG. 7), region 1114,when positioned against the skin, can expose vacuum to that portion ofthe skin proximate surface 1104 of the device and abutting the chamber.

Device 1100 also includes a transfer component actuator 1116 which, asillustrated, includes a proximate portion 1118 which can be addressed bya user of the device (who may be the same or different from the subjectthe device is administered to) and a distal portion 1120 for addressingsubstance transfer component 1108 via flexible structure 1112. Proximalportion 1118 and distal portion 1120 are, in the device illustrated,opposite ends of a single component but, as would be understood by thoseof ordinary skill in the art, the actuator can include a plurality ofindividual components operably linked in any way necessary to performactuation as will be described.

As will be understood, FIG. 7 is a cross-section of a deviceillustrating various components and channels within the device. As willalso be understood by those of ordinary skill in the art, differentarrangements of devices and channels are contemplated herein so long asthe purpose of the device described herein is met. In this figure,actuator 1116 is directly connected to or otherwise operably linked to areversibly deformable structure 1122 which, in the device illustrated,is in the form of a “snap dome,” the function and use of which will bedescribed below. The snap dome in this figure has an approximatelycircular profile. The structure may define an interior and a peripherywhich, if not circular, may include a plurality of tabs, protrusions, orthe like sufficient for support of structure 1122 within the device. Asillustrated, a plurality of tabs (or the essentially circular perimeterof) the device are supported within holders 1124, and the center, snapdome portion of the device is operably linked to actuator 1116, suchthat movement of the central portion of snap dome 1122 and the peripheryof the snap dome can be controlled independently of each other. Holders1124 are directly connected to or otherwise operably linked to anactuator retraction component 1126 which, in the device illustrated, canbe a ring-shaped structure positioned under and supporting holders 1124.Holders 1124 can be individual holders and/or a ring-like structuresurrounding the periphery of snap dome 1122. A series of one, two, ormore support members (e.g., 1130) are positioned near the top of device1100 and serve to define a series of channels for sample flow, vacuumcontrol, or the like as will be described.

Turning now to channels defined within the device, as described above,region 1114, when the device is positioned against skin, can serve toexpose a portion of the skin defined by the periphery of the region to avacuum, to substance transfer component 1108 as it moves toward and/oraway from the skin, and/or to transfer a substance from or to thesubject. Region 1114 can house a substance for transfer to the subject,in the form of a pharmaceutical composition or the like, optionallyloaded on substance transfer component 1108. Where blood and/orinterstitial fluid is drawn from a subject, region 1114 can serve tointroduce the substance into the device from the subject.

A channel 1132 connects region 1114 to other portions of the device inthis example. Channel 1132 can be used to deliver a substance to region1114 for transfer to a subject, or for application of a vacuum to region1114, and/or for receiving of a substance from a subject. The remainderof the description of device 1100 will be made within the context ofreceiving a substance such as blood and/or interstitial fluid from asubject, but it is to be understood that substances can also bedelivered via various channels. Channel 1132 typically emanates in onedirection from region 1114 although a plurality of channels can emanatefrom the region, arranged radially or otherwise relative to the centerof the device. In device 1100, channel 1132 first passes laterally fromthe center of the device and then upwardly where, near the top of thedevice, it can, optionally, include one wall defining a window 1134through which a user of the device can observe transfer of a substance,or through which analysis of a substance may occur. It can also itselfdefine a reservoir, in whole or in part, or be connected to an internalor an external reservoir for maintaining, storing, and/or transferring asubstance drawn from a subject. As shown here, it can be connected to asubstance collection reservoir 1136 which, as illustrated, is adisc-shaped reservoir formed in the device housing and surrounding thecenter of the device including actuator 1116 and related components.

Device 1100, illustrated as one example of devices provided by theinvention, includes a vacuum chamber for applying a vacuum proximate theskin of a subject for withdrawing a substance from the skin. Asillustrated, vacuum chamber 1138 is positioned in a central portion ofthe device surrounding actuator 1116, although it can be providedanywhere in or proximate the device. The vacuum chamber can be evacuatedto an appropriate level just prior to use, or the device can bepre-packaged under vacuum as described elsewhere herein. As illustrated,vacuum chamber 1138 is in fluid communication with substance collectionreservoir 1136 but, in its initial state and prior to use, a membrane orother component, such as support member 1128, separates channel 1132connecting it to region 1102. In the device illustrated, a vacuumactuation component 1140 can be actuated to puncture the membrane orother component (e.g., 1128) and thereby connect vacuum chamber 1138with channel 1132, at an appropriate time during use of the device. Inother embodiments, actuator 1116 and vacuum actuation component 1140 canbe combined into a single button or operably linked so that only oneoperation is needed to actuate both the microinsertion objects and thevacuum.

Reversibly deformable structure (or, as shown, a snap dome) 1122 can beprovided in a variety of forms including a monostable or bistableconfiguration. In the embodiment illustrated, a bistable configurationis illustrated including first and second low energy or stableconfigurations separated by a relatively high energy or unstableconfiguration. As shown, the reversibly deformable structure 1122 isshown in a “cocked” or predeployed position.

The reversibly deformable structure (or the flexible concave member) maybe formed from any suitable material, for example, a metal such asstainless steel (e.g., 301, 301LN, 304, 304L, 304LN, 304H, 305, 312,321, 321H, 316, 316L, 316LN, 316Ti, 317L, 409, 410, 430, 440A, 440B,440C, 440F, 904L), carbon steel, spring steel, spring brass, phosphorbronze, beryllium copper, titanium, titanium alloy steels, chromevanadium, nickel alloy steels (e.g., Monel 400, Monel K 500, Inconel600, Inconel 718, Inconel x 750, etc.), a polymer (e.g.,polyvinylchloride, polypropylene, polycarbonate, etc.), a composite or alaminate (e.g., comprising fiberglass, carbon fiber, bamboo, Kevlar,etc.), or the like.

The reversibly deformable structure may be of any shape and/or size. Inone embodiment, the reversibly deformable structure is a flexibleconcave member. In some cases, the reversibly deformable structure mayhave a generally domed shape (e.g., as in a snap dome), and be circular(no legs), or the reversibly deformable structure may have other shapes,e.g., oblong, triangular (3 legs), square (4 legs), pentagonal (5 legs),hexagonal (6 legs), spider-legged, star-like, clover-shaped (with anynumber of lobes, e.g., 2, 3, 4, 5, etc.), or the like. The reversiblydeformable structure may have, in some embodiments, a hole, dimple, orbutton in the middle. The reversibly deformable structure may also havea serrated disc or a wave shape. In some cases, a flow activator or asubstance transfer component may be mounted on the reversibly deformablestructure. In other cases, however, the flow activator or substancetransfer component is mounted on a separate structure which is driven oractuated upon movement of the reversibly deformable structure.

In one set of embodiments, the reversibly deformable structure is notplanar, and has a portion that can be in a first position (a “cocked” orpredeployed position) or a second position (a “fired” or deployedposition), optionally separated by a relatively high energyconfiguration. In some cases, both the first position and the secondposition are stable (i.e., the structure is bistable), althoughconversion between the first position and the second position requiresthe structure to proceed through an unstable configuration.

In some cases, surprisingly, the distance or separation between thefirst position and the second position is relatively small. Suchdistances or separations may be achieved using snap domes or otherconfigurations such as those described herein, in contrast to springs orother devices which require longer translational or other movements. Forexample, the perpendicular distance (i.e., in a direction away from theskin) in the reversibly deformable structure between the top of thestructure and the bottom of the structure (excluding the substancetransfer component) when the device containing the structure is placedon the skin of a subject (i.e., the height of the device once it hasbeen placed no the skin of the subject) may be no more than about 5 mm,no more than about 4 mm, no more than about 3 mm, no more than about 2mm, no more than about 1 mm in some cases, no more than about 0.8 mm, nomore than about 0.5 mm, or no more than about 0.3 mm. In one set ofembodiments, the distance is between about 0.3 mm and about 1.5 mm. Inanother set of embodiments, the reversibly deformable structure may havea greatest lateral dimension (parallel to the skin) when the devicecontaining the structure is placed on the skin of a subject of no morethan about 50 mm, no more than about 40 mm, no more than about 30 mm, nomore than about 25 mm, no more than about 20 mm, no more than about 15mm, no more than about 5 mm, no more than about 4 mm, no more than about3 mm, no more than about 2 mm, no more than about 1 mm in some cases, nomore than about 0.8 mm, no more than about 0.5 mm, or no more than about0.3 mm. In one set of embodiments, the distance is between about 0.3 mmand about 1.5 mm.

In some embodiments, the device may exhibit a relatively high successrate of receiving of fluid from various subjects. For example, in someembodiments, the success rate of receiving at least about 5 microlitersof blood from a subject may be at least about 95%, at least about 97%,at least about 98%, at least about 99%, or at least about 100%, ascompared to prior art devices (e.g., lancet devices) which typicallyhave success rates of less than 95%. In other embodiments, the volumemay be at least about 0.1 microliters, at least about 0.3 microliters,at least about 0.5 microliters, at least about 1 microliter, at leastabout 3 microliters, at least about 5 microliters, or at least about 10microliters. For instance, a population of subjects may be tested withboth a prior art device and a device of the invention such that eachsubject is tested with both devices in a suitable location (e.g., theforearm) when determining success probabilities, where the population ofsubjects is randomly chosen. The population may be for example, at least10, at least 100, at least 1,000, at least 10,000 or more individuals.

Use of device 1100 will now be described in the context of withdrawing asubstance such as blood from a subject. Device 1100 is placed againstthe skin of a subject such that at least a portion of surface 1104contacts the skin. Prior to use, a cover member (not shown) can coversurface 1104 of the device and can cover region 1114, to protect surface1104 and region 1114 from contaminants, etc. optionally maintaining theinterior of the device in a sterile condition. The cover can be peeledoff or otherwise removed from the device, and the device placed againstthe skin, optionally adhering to the skin. Vacuum actuation component1140 can be actuated to expose channel 1132 and region 1114 to vacuum atany time, including before, simultaneously, or after actuation ofsubstance transfer component 1108. In one arrangement, vacuum actuationcomponent 1140 is actuated to apply vacuum to region 1114 prior toactuation to substance transfer component 1108, thereby to create avacuum against the skin proximate region 1114 prior to use. Actuation ofactuator 1116 can take place before or after deployment of vacuum.

When transfer component actuator 1116 is actuated by a user (e.g., whenproximal portion 1118 is depressed downwardly as shown in the figure),distal portion 1120 engages substance transfer component 1108(optionally via flexible structure 1112) to drive it toward the skin. Insome embodiments, foil 1128 is first broken, then component 1126 iscompressed, before flexible structure 1112 is stretched and thereversibly deformable structure 1122 of the device fires or is actuated.Membranes or other members 1112, 1128, or 1130 may have, in some cases,sufficient flexibility and/or elasticity to allow actuator 1116 to drivesubstance transfer component 1108 sufficiently distally (downwardly, asshown) to engage the skin of the subject and carry out the desiredfunction of the device. Various gaskets, bearings, or membranes as showncan be used for this function. Where support member 1128 is a foil orthe like used for the purpose of initially separating vacuum reservoir1138 from channel 1132 (e.g., prior to use), when actuator 1116 is moveddownwardly, vacuum actuation component 1140 may rupture support member1128 proximate actuator 1116, or flexibly deform as need be, so long asmember 1130 (or another component) serves to allow actuator 1116 toslide within the device while maintaining sufficient vacuum in vacuumreservoir 1138 and related channels for use of the device.

When substance transfer component 1108 (e.g., insertion objects) engagesthe skin of the subject and facilitates receiving of a substance fromthe skin and/or from beneath the skin of the subject, a vacuum can drawthe substance into region 1114, through channel or channels 1132, andinto substance collection reservoir 1136. In this process, actuator 1116first urges structure 1122 from its first stable configuration to arelatively unstable configuration and beyond that point, at which pointthe structure 1122 rapidly moves to a second stable configurationassociated with downward driving of actuator 1116 to quickly driveaccess substance transfer component 1108 into and/or through the skin.

After that point, if it is desirable for access substance transfercomponent 1108 to be received from the skin, then a variety oftechniques can be used to do so. In the device illustrated, retractioncomponent 1126 drives holder 1124 upwardly, retracting structure 1122and actuator 1116 from substance transfer component 1108. At that point,actuator 1116 can be operably linked to transfer component 1108 andwithdraw the transfer component, or it can move freely relative tosubstance transfer component 1108, whereby flexible structure 1112(e.g., an elastic membrane) or other component can withdraw substancetransfer component 1108 from the skin. Again, in the device illustrated,retraction component 1126 can itself be a reversibly deformablestructure such as a leaf spring, coil spring, foam, or the like. Duringuse, when actuator 1116 is driven downwardly, retraction component 1126is first compressed and, depending upon the size and arrangement ofcomponents 1126, 1124, 1122, 1116 and 1108, during compression,substance transfer component 1108 can be driven downwardly to someextent. At the point at which retraction component 1126 is compressedand provides a sufficient resistance force, reversibly deformablestructure 1122 can be urged from its first configuration through anunstable configuration and can return to its second configuration,driving substance transfer component 1108 against the skin. Then, uponrelease of user pressure (or other actuation, which can be automatic)from actuator 1116, retraction component 1126 can expand and, withstructure 1122 optionally remaining in its second, downwardly-drivenlow-energy configuration, actuator 1116 can be retracted and substancetransfer component 1108 retracted from the skin.

Referring now to FIGS. 8A and 8B, device 1150 is illustratedschematically. Device 1150 is similar to and can be consideredessentially identical to device 1100 in all aspects other than thosedescribed here with respect to FIGS. 8A and 8B. As such, the reader willobserve that not all components are provided, although other componentssimilar to those of device 1100 can exist. One way in which device 1150differs from device 1100 is that in device 1150, in the pre-deploymentor post-deployment retracted configuration, membrane 1112 is drawnproximally (upwardly) as illustrated in FIG. 8B. Membrane 1112 is in aless-stressed lower-energy configuration as shown in FIG. 8A whenretraction component 1126 is compressed and substance transfer component1108 is driven into and/or through the skin. Devices 1100, 1150, andother similar devices are one way to enact a triggering mechanism thatcan move a substance transfer component 1108 or other similar transfercomponent relative to the skin in particularly advantageous ways.Examples of triggering mechanisms include, in addition to the examplesshown in FIGS. 7 and 8, blasting caps, explosives, other chemicalreactions, solenoids or other electrical interactions, pneumatics (e.g.,compressed air), other thermal interactions or mechanical interactions,or the like.

In one set of embodiments, the triggering mechanism may move transfercomponent 1108 from a fully predeployed position (e.g., as shown in FIG.7) to a fully deployed position in which substance transfer component1108 is fully engaged with the skin, in a short period of time. In oneembodiment, that period of time is less than about 0.01 seconds, and inother embodiments, less than about 0.009 seconds, less than about 0.008seconds, less than about 0.007 seconds, less than about 0.006 seconds,less than about 0.005 seconds, less than about 0.004 seconds, less thanabout 0.003 seconds, less than about 0.002 seconds, less than about0.001 seconds, less than about 0.0005 seconds, less than about 0.00025,or less than about 0.0001 seconds.

In another embodiment, substance transfer component 1108 moves quicklyrelative to skin during deployment via the triggering mechanism,reaching a speed of at least about 4 m/s, at least about 5 m/s, at leastabout 6 m/s, at least about 7 m/s, at least about 8 m/s, at least about10 m/s, at least about 12 m/s, at least about 15 m/s, or at least about20 m/s at the point at which substance transfer component 1108 firsttouches the skin during deployment.

In some cases, substance transfer component 1108 achieves relativelyhigh accelerations due to the triggering mechanism, for example, atleast about 4 m/s², about 6 m/s², about 8 m/s², about 10 m/s², about 12m/s², about 15 m/s², or about 20 m/s², at least about 30 m/s², at leastabout 50 m/s², at least about 100 m/s², at least about 300 m/s², atleast about 500 m/s², at least about 1,000 m/s², at least about 3,000m/s², at least about 5,000 m/s², at least about 10,000 m/s², at leastabout 30,000 m/s², at least about 50,000 m/s², at least about 100,000m/s², at least about 200,000 m/s², or at least about 300,000 m/s². Insome embodiments, the substance transfer component 1108 is acceleratedfor relatively short periods of time, e.g., less than about 1 s, lessthan about 300 ms, less than about 100 ms, less than about 30 ms, lessthan about 10 ms, less than about 3 ms, or less than about 1 ms, and/orover relatively short distances, e.g., less than about 5 mm, less thanabout 4 mm, less than about 3 mm, less than about 2 mm, less than about1 mm, less than about 800 micrometers, less than 600 micrometers, lessthan 500 micrometers, less than 400 micrometers, less than about 300micrometers, less than about 200 micrometers, less than about 100micrometers, less than about 50 micrometers, etc.

Significant forces can be applied to substance transfer component 1108as it moves relative to the skin via the triggering mechanism. In oneset of embodiments, substance transfer component 1108, at the point atwhich it first contacts the skin, is driven by a force created at leastin part by the triggering mechanism of at least about 6 micronewtons,about 8 micronewtons, about 10 micronewtons, about 12 micronewtons, orabout 15 micronewtons.

In another set of embodiments, substance transfer component 1108 appliesa pressure to the skin, during deployment caused by the triggeringmechanism, of at least about 100 N/m², at least about 300 N/m², at leastabout 1,000 N/m², at least about 3,000 N/m², etc. In force assessment,the area can be measured as the area of skin displaced by the transfercomponent at full deployment, e.g., the area of the skin ruptured by thetotal of the cross sectional area of all substance transfer componentsinserted into the skin, at the top surface of the skin.

In some cases, the substance transfer component is forced into the skinvia the triggering mechanism with a force sufficient to insert thesubstance transfer component into or through the skin to an averagedepth of at least about 60% of the substance transfer component (or theaverage length of the substance transfer components, if more than one isused, e.g., as in an array of needles or microneedles). In some cases,the depth is at least about 65%, at least about 70%, at least about 75%,at least about 80%, at least about 85%, at least about 90%, or at leastabout 95% of the substance transfer component, e.g., the length of theneedle or the microneedle inserted into the skin.

Devices of the invention can provide significant advantage in someembodiments. For example, triggering mechanisms able to move substancetransfer components in short time periods, and/or at high velocities,and/or with high forces, and/or with high pressure, and/or driverelatively short substance transfer components such as microinsertionobjects or microneedles relatively deeply into the skin and/or throughthe skin, and/or any combination of the above can provide significantadvantage. In some embodiments, these features can provide bettercontrol of substance delivery or receiving. Better mechanical stabilitycan be provided in some cases by shorter substance transfer components(e.g., bending and/or buckling can be avoided) and relatively shortersubstance transfer components, designed to be driven relativelycompletely (for example, through nearly all of their entire length) intothe skin may offer better control of penetration in some embodiments. Ifbetter control of penetration can be achieved, better delivery orreceiving can also be achieved in some cases, for example, resulting inless pain or essentially painless deployment.

Moreover, if substance transfer components are used to deliver asubstance such as a pharmaceutical composition into or through the skin,more precise delivery can be provided, according to certain embodiments.More precise control over depth of insertion of the substance transfercomponents (e.g., by using devices designed to insert the substancetransfer components essentially fully) yield more control over theamount of pharmaceutical substance inserted into the skin by thesubstance transfer components, in some embodiments. Furthermore, quickand/or high velocity, and/or high force and/or pressure application ofmicroinsertion objects to the skin may in certain embodiments result inlower pain or painless deployment.

Another example is illustrates in FIG. 9A. This figure shows a device800 including a flow activator (e.g., microneedle array 833), areversibly deformable structure (e.g., snap dome 832), an activator(e.g., activation button 831), a retraction mechanism (e.g., siliconefoam 835), and structural components constructed from multiple layers ofpolycarbonate bonded together using a double-sided adhesive, such as 3M1509 or 3M 1513 tape. The microneedle arrays can be bonded to laminatedpost 837 on the underside of a snap dome. Structural components 838, aswell as post 837, are formed from polycarbonate and 3M 1509 or 3M 1513adhesive. The arrays may range in needle number (4 to 28 needles),needle length (350 to 1000 micrometers), and/or arrangement (square,rectangular, and circular arrays), with array footprints of less than 3mm in diameter, where the “footprint” is the area of the base to whichthe needles are attached.

In use, the device may be charged by setting the snap dome in a highenergy position, placing the base of the device against the skin of asubject (with the needle tips pointing towards the skin), and pushingbutton 831 on the top of the device. As the button is pressed, siliconefoam 835 compresses, positioning the needle tips in close proximity tothe skin through opening 840. When the foam is fully compressed, theforce causes the button to collapse, which then translates to the backof the snap dome to cause it to move to a stable low energy state. Therelease of energy from the snap dome changing states accelerates themicroneedle array forward through the opening in the base and insertsthe needles into the skin. When the force on the button is released, thesilicone foam expands to its original height and retracts the needlesfrom the skin in the process.

Yet another example is illustrates in FIG. 9B. This device includes avacuum chamber comprising layers of polycarbonate, polyethyleneterephthalate glycol (PETG), and silicone bonded together using adouble-sided adhesive, such as 3M 1509 or 3M 1513 tape. The chamber isapproximately 2.7 cm in diameter and 0.6 cm high, with cup opening 858in the base that ranges from 3 to 7 mm in diameter. The vacuum chambermay be attached to the skin of a subject over the microneedle insertionsite using adhesive 857, such as 3M 1509 or Katecho 10G hydrogel. Avacuum source (i.e., vacuum pump, syringe, vacuum reservoir, etc.) canbe connected to the chamber using hypodermic needle 859 inserted throughsilicone layer 852, and vacuum (i.e., 30 to 70 kPa) may be applied tothe site for a fixed period of time (i.e., 10 s to 10 min). Theapplication of vacuum causes blood to flow from the skin punctures intothe vacuum chamber.

Still another example is shown in FIG. 9C. In this figure, theintegrated device 800 includes a support structure 801 for applicationto the skin of the subject. The structure is constructed from multiplelayers of polyethylene terephthalate glycol (PETG). These layers may beformed into the requisite geometry by machining sheet stock or injectionmolding. The individual layers are bonded together using double-sidedadhesive, such as 3M 1513 tape, but may also be bonded usingnon-adhesive methods such as ultrasonic welding or laser welding. Thesupport structure is attached to the skin of a subject using an adhesive802, such as Katecho 10G hydrogel.

The left side of the support structure in FIG. 9C houses the componentsnecessary to insert a microneedle array into the skin. These componentsinclude a circular microneedle array of sixteen 750 micrometers longneedles 803 actuated by the extraction activator 804 comprising areversibly deformable structure (e.g., a snap dome 805), a button 806,and a foam return mechanism 807. Pressing the button initiallycompresses the foam, bringing the microneedles into close proximity withthe skin, and then fires the snap dome, moving it from the first stableconfiguration to the second stable configuration. The movement of thesnap dome accelerates and inserts the microneedles into the skin.Releasing the pressure on the button allows the foam to expand andretract the microneedles from the skin.

The right side of the support structure shown in FIG. 9C comprises aself contained vacuum chamber 808 fluidically connected to a storagechamber 809. The storage chamber is fluidically connected to theextraction activator by a microfluidic channel 810. Pressing the button811 breaks a seal and causes the fluidically connected components to beevacuated as well as reduces the pressure on the skin below themicroneedle array. This reduced pressure urges blood from the skin intothe microfluidic channel and into the storage chamber.

In certain aspects, the device may also contain an activator. Theactivator may be constructed and arranged to cause exposure of the flowactivator to the skin upon activation of the activator. For example, theactivator may cause a chemical to be released to contact the skin, oneor more needles or microneedles to be driven into the skin, a vacuum tobe applied to the skin, a jet of fluid to be directed to the skin, orthe like. The activator may be activated by the subject, and/or byanother person (e.g., a health care provider), or the device itself maybe self-activating, e.g., upon application to the skin of a subject. Theactivator may be activated once, or multiple times in some cases. Insome embodiments, the activator, or at least a portion thereof, may alsoserve as a seal, as discussed herein.

The device may be activated, for example, by pushing a button, flippinga switch, moving a slider, turning a dial, or the like. The subject,and/or another person, may activate the activator. In some cases, thedevice may be remotely activated. For example, a health care providermay send an electromagnetic signal which is received by the device inorder to activate the device, e.g., a wireless signal, a Bluetoothsignal, an Internet signal, a radio signal, etc.

Any or all of the arrangements described herein can be providedproximate a subject, for example on or proximate the skin of a subject,in various aspects. Activation of the devices can be carried out in avariety of ways, e.g., as described herein. For example, an on-skindevice can be in the form of a patch or the like, optionally includingmultiple layers for activation, sensing, fluid flow, etc. In oneembodiment, a patch or a device can be applied to a subject and a regionof the patch or device activated (e.g., pushed, pressed, or tapped by auser) to inject a needle or a microneedle, or other flow activator, soas to access interstitial fluid or blood. The same or a differentactivation action, e.g., tapping or pushing action, can activate avacuum source, open and/or close one or more of a variety of valves, orthe like. The device can be a simple one in which it is applied to theskin and operates automatically (where e.g., application to the skin ofthe device allows access to interstitial fluid or blood, and deliversand/or withdraws fluid) or the patch or other device can be applied tothe skin and one tapping or other activation action can cause fluid toflow through administration of one or more needles or microneedles (orother flow activator), opening of a valve, activation of vacuum, etc.,or any combination thereof. Any number of activation actions can becarried out by a user repeatedly pushing, tapping, etc. a location orselectively, sequentially, and/or periodically activating a variety ofswitches.

In another arrangement, activation of one or more needles ormicroneedles, creation of suction blisters, opening and/or closing ofvalves, and other techniques to facilitate withdraw of a fluid can becarried out electronically or in other manners facilitated by thesubject or by an outside controlling entity (e.g., another user of thedevice). For example, a device or patch can be provided proximate theskin of a subject and a radio frequency, electromagnetic, or othersignal can be provided by a nearby controller or a distant source toactivate any of the needles, flow activators, blister devices, valves,or other components of the devices described so that receiving of afluid can be carried out as desired.

According to one aspect of the invention, the device is of a relativelysmall size. In some embodiments, the device may be sized such that it iswearable and/or carryable by a subject. For example, the device may beself-contained, needing no wires, cables, tubes, external structuralelements, or other external support. The device may be positioned on anysuitable position of the subject, for example, on the arm or leg, on theback, on the abdomen, etc.

In some embodiments, the device may be a handheld device that is appliedto the surface of the skin of a subject. In some cases, however, thedevice may be sufficiently small or portable that the subject canself-administer the device. In certain embodiments, the device may alsobe powered. In some instances, the device may be applied to the surfaceof the skin, and is not inserted into the skin. In other embodiments,however, at least a portion of the device may be inserted into the skin,for example, mechanically. For example, in one embodiment, the devicemay include a cutter, such as a hypodermic needle, a knife blade, apiercing element (e.g., a solid or hollow needle), or the like, asdiscussed herein.

In another set of embodiments, the device may be an electrical and/or amechanical device applicable or affixable to the surface of the skin,e.g., using adhesive, or other techniques such as those describedherein. For example, in one set of embodiments, the device may include asupport structure that contains an adhesive that can be used toimmobilize the device to the skin. The adhesive may be permanent ortemporary, and may be used to affix the device to the surface of theskin. The adhesive may be any suitable adhesive, for example, a pressuresensitive adhesive, a contact adhesive, a permanent adhesive, acyanoacrylate, glue, gum, hot melts, an epoxy, a hydrogel, ahydrocolloid, or the like. In some cases, the adhesive is chosen to bebiocompatible or hypoallergenic.

In another set of embodiments, the device may be mechanically held tothe skin. For instance, the device may include mechanical elements suchas straps, belts, buckles, strings, ties, elastic bands, or the like.For example, a strap may be worn around the device to hold the device inplace against the skin of the subject. In yet another set ofembodiments, a combination of these and/or other techniques may be used.As one non-limiting example, the device may be affixed to a subject'sarm or leg using adhesive and a strap.

Thus, in some embodiments, the device may be affixed or held onto thesurface of the skin using any suitable technique, e.g., using adhesives,mechanical elements such as straps, belts, buckles, strings, ties,elastic bands, or the like. In some cases, the device may be positionedon the subject such that the subject is able to move around (e.g.,walking, exercising, typing, writing, drinking or eating, using thebathroom, etc.) while wearing the device. For example, the device mayhave a mass and/or dimensions such that the subject is able to wear thedevice for at least about 5 minutes, and in some cases for longerperiods of time, e.g., at least about 10 minutes, at least about 15minutes, at least about 30 minutes, at least about 45 minutes, at leastabout 1 hour, at least about 3 hours, at least 5 hours, at least about 8hours, at least about 1 day, at least about 2 days, at least about 4days, at least about 1 week, at least about 2 weeks, at least about 4weeks, etc.

In some embodiments, the device is relatively lightweight. For example,the device may have a mass of no more than about 1 kg, no more thanabout 300 g, no more than about 150 g, no more than about 100 g, no morethan about 50 g, no more than about 30 g, no more than about 25 g, nomore than about 20 g, no more than about 10 g, no more than about 5 g,or no more than about 2 g. For instance, in various embodiments, thedevice has a mass of between about 2 g and about 25 g, a mass of betweenabout 2 g and about 10 g, a mass of between 10 g and about 50 g, a massof between about 30 g and about 150 g, etc.

The device, in some cases, may be relatively small. For example, thedevice may be constructed and arranged to lie relatively close to theskin. Thus, for instance, the device may have a largest verticaldimension, extending from the skin of the subject when the device ispositioned on the skin, of no more than about 25 cm, no more than about10 cm, no more than about 7 cm, no more than about 5 cm, no more thanabout 4 cm, no more than about 3 cm, no more than about 2 cm, no morethan about 1 cm, no more than about 8 mm, no more than about 5 mm, nomore than about 3 mm, no more than about 2 mm, no more than about 1 mm,or no more than about 0.5 mm. In some cases, the device may have alargest vertical dimension of between about 0.5 cm and about 1 cm,between about 2 and about 3 cm, between about 2.5 cm and about 5 cm,between about 2 cm and about 7 cm, between about 0.5 mm and about 7 cm,etc.

In another set of embodiments, the device may have a relatively smallsize. For example, the device may have a largest lateral dimension(e.g., parallel to the skin) of no more than about 25 cm, no more thanabout 10 cm, no more than about 7 cm, no more than about 5 cm, no morethan about 3 cm, no more than about 2 cm, or no more than about 1 cm. Insome cases, the device may have a largest lateral dimension of betweenabout 0.5 cm and about 1 cm, between about 2 and about 3 cm, betweenabout 2.5 cm and about 5 cm, between about 2 cm and about 7 cm, etc.

Combinations of these and/or other dimensions are also possible in otherembodiments. As non-limiting examples, the device may have a largestlateral dimension of no more than about 5 cm, a largest verticaldimension of no more than about 1 cm, and a mass of no more than about25 g; or the device may have a largest lateral dimension of no more thanabout 5 cm, a largest vertical dimension of no more than about 1 cm, anda mass of no more than about 25 g; etc.

The device, in certain aspects, may contain a portion able to determinea fluid removed from the skin. For example, in some cases, a device canbe applied to the skin, and activated to withdraw fluid from the skinand/or beneath the skin of the subject. The device, or a portionthereof, may then be processed to determine the fluid and/or an analytewithin the fluid, alone or with an external apparatus. For example,fluid may be received from the device, and/or the device may containsensors or agents able to determine the fluid and/or an analytesuspected of being contained in the fluid. For example, a portion of thedevice may contain a sensor, or reagents able to interact with ananalyte contained or suspected to be present within the received fluidfrom the skin of the subject, for example, a marker for a disease state.For example, the sensor may determine plasma, serum, or blood that hasbeen received from the subject.

The sensor may be embedded within or integrally connected to the device,or positioned remotely but with physical, electrical, and/or opticalconnection with the device so as to be able to sense a chamber within orfluid from the device. For example, the sensor may be in fluidiccommunication with fluid received from a subject, directly, via amicrofluidic channel, an analytical chamber, etc. The sensor may be ableto sense an analyte, e.g., one that is suspected of being in a fluidreceived from a subject. For example, a sensor may be free of anyphysical connection with the device, but may be positioned so as todetect the results of interaction of electromagnetic radiation, such asinfrared, ultraviolet, or visible light, which has been directed towarda portion of the device, e.g., a chamber within the device. As anotherexample, a sensor may be positioned on or within the device, and maysense activity in a chamber by being connected optically to the chamber.Sensing communication can also be provided where the chamber is incommunication with a sensor fluidly, optically or visually, thermally,pneumatically, electronically, or the like, so as to be able to sense acondition of the chamber. As one example, the sensor may be positioneddownstream of a chamber, within a channel such a microfluidic channel,on an external apparatus, or the like.

Thus, the invention provides, in certain embodiments, sensors able todetermine an analyte. Such determination may occur within the skin,and/or externally of the subject, e.g., within a device on the surfaceof the skin, depending on the embodiment. “Determine,” in this context,generally refers to the analysis of a species, for example,quantitatively or qualitatively, and/or the detection of the presence orabsence of the species. “Determining” may also refer to the analysis ofan interaction between two or more species, for example, quantitativelyor qualitatively, and/or by detecting the presence or absence of theinteraction, e.g. determination of the binding between two species. Thespecies may be, for example, a bodily fluid and/or an analyte suspectedof being present in the bodily fluid. “Determining” also means detectingor quantifying interaction between species or identifying or otherwiseassessing one or more characteristics of the sample, such as thepresence and/or concentration of one or more species, a physical and/orchemical property of the sample, etc.

Fluids received from the skin and/or from beneath the skin of thesubject will often contain various analytes within the body that areimportant for diagnostic purposes, for example, markers for variousdisease states, such as glucose (e.g., for diabetics); other exampleanalytes include ions such as sodium, potassium, chloride, calcium,magnesium, and/or bicarbonate (e.g., to determine dehydration); gasessuch as carbon dioxide or oxygen; H⁺ (i.e., pH); metabolites such asurea, blood urea nitrogen or creatinine; hormones such as estradiol,estrone, progesterone, progestin, testosterone, androstenedione, etc.(e.g., to determine pregnancy, illicit drug use, or the like); orcholesterol. Other examples include insulin, or hormone levels. Stillother analytes include, but not limited to, high-density lipoprotein(“HDL”), low-density lipoprotein (“LDL”), albumin, alanine transaminase(“ALT”), aspartate transaminase (“AST”), alkaline phosphatase (“ALP”),bilirubin, lactate dehydrogenase, etc. (e.g., for liver function tests);luteinizing hormone or beta-human chorionic gonadotrophin (hCG) (e.g.,for fertility tests); prothrombin (e.g., for coagulation tests);troponin, BNT or B-type natriuretic peptide, etc., (e.g., as cardiacmarkers); infectious disease markers for the flu, respiratory syncytialvirus or RSV, etc.; or the like.

The sensor may be, for example, a pH sensor, an optical sensor, anoxygen sensor, a sensor able to detect the concentration of a substance,or the like. Non-limiting examples of sensors useful in the inventioninclude dye-based detection systems, affinity-based detection systems,microfabricated gravimetric analyzers, CCD cameras, optical detectors,optical microscopy systems, electrical systems, thermocouples andthermistors, pressure sensors, etc. Those of ordinary skill in the artwill be able to identify other suitable sensors. The sensor can includea colorimetric detection system in some cases, which may be external tothe device, or microfabricated into the device in certain cases. As anexample of a colorimetric detection system, if a dye or a fluorescententity is used (e.g. in a particle), the colorimetric detection systemmay be able to detect a change or shift in the frequency and/orintensity of the dye or fluorescent entity.

Examples of sensors include, but are not limited to, pH sensors, opticalsensors, ion sensors, colorimetric sensors, a sensor able to detect theconcentration of a substance, or the like, e.g., as discussed herein.For instance, in one set of embodiments, the device may include an ionselective electrode. The ion selective electrode may be able todetermine a specific ion and/or ions such as K⁺, H⁺, Na⁺, Ag⁺, Pb²⁺,Cd²⁺, or the like. Various ion selective electrodes can be obtainedcommercially. As a non-limiting example, a potassium-selective electrodemay include an ion exchange resin membrane, using valinomycin, apotassium channel, as the ion carrier in the membrane to providepotassium specificity.

Examples of analytes that the sensor may be used to determine include,but are not limited to, pH or metal ions, proteins, nucleic acids (e.g.DNA, RNA, etc.), drugs, sugars (e.g., glucose), hormones (e.g.,estradiol, estrone, progesterone, progestin, testosterone,androstenedione, etc.), carbohydrates, or other analytes of interest.Other conditions that can be determined can include pH changes, whichmay indicate disease, yeast infection, periodontal disease at a mucosalsurface, oxygen or carbon monoxide levels which indicate lungdysfunction, and drug levels, e.g., legal prescription levels of drugssuch as coumadin, other drugs such as nicotine, or illegal drugs such ascocaine. Further examples of analytes include those indicative ofdisease, such as cancer specific markers such as CEA and PSA, viral andbacterial antigens, and autoimmune indicators such as antibodies todouble stranded DNA, indicative of Lupus. Still other conditions includeexposure to elevated carbon monoxide, which could be from an externalsource or due to sleep apnea, too much heat (important in the case ofbabies whose internal temperature controls are not fullyself-regulating) or from fever. Still other potentially suitableanalytes include various pathogens such as bacteria or viruses, and/ormarkers produced by such pathogens.

As additional non-limiting examples, the sensor may contain an antibodyable to interact with a marker for a disease state, an enzyme such asglucose oxidase or glucose 1-dehydrogenase able to detect glucose, orthe like. The analyte may be determined quantitatively or qualitatively,and/or the presence or absence of the analyte within the received fluidmay be determined in some cases. Those of ordinary skill in the art willbe aware of many suitable commercially-available sensors, and thespecific sensor used may depend on the particular analyte being sensed.For instance, various non-limiting examples of sensor techniques includepressure or temperature measurements, spectroscopy such as infrared,absorption, fluorescence, UV/visible, FTIR (“Fourier Transform InfraredSpectroscopy”), or Raman; piezoelectric measurements; immunoassays;electrical measurements, electrochemical measurements (e.g.,ion-specific electrodes); magnetic measurements, optical measurementssuch as optical density measurements; circular dichroism; lightscattering measurements such as quasielectric light scattering;polarimetry; refractometry; chemical indicators such as dyes; orturbidity measurements, including nephelometry.

In one set of embodiments, a sensor in the device may be used todetermine a condition of the blood, interstitial fluid, or other fluidpresent within the device. For example, the sensor may indicate thecondition of analytes commonly found within the blood or interstitialfluid, for example, O₂, K⁺, hemoglobin, Na⁺, glucose, or the like. As aspecific non-limiting example, in some embodiments, the sensor maydetermine the degree of hemolysis within blood contained within thedevice. Without wishing to be bound by any theory, it is believed thatin some cases, hemolysis of red blood cells may cause the release ofpotassium ions and/or free hemoglobin into the blood. By determining thelevels of potassium ions, and/or hemoglobin (e.g., by subjecting thedevice and/or the blood to separate cells from plasma, then determininghemoglobin in the plasma using a suitable colorimetric assay), theamount of blood lysis or “stress” experienced by the blood containedwithin the device may be determined. Accordingly, in one set ofembodiments, the device may indicate the usability of blood (or otherfluid) contained within the device, e.g., by indicating the degree ofstress or the amount of blood lysis. Other examples of devices suitablefor indicating the usability of blood (or other fluid) contained withinthe device are also discussed herein (e.g., by indicating the amount oftime blood has been contained in the device, the temperature history ofthe device, etc.).

In some embodiments, an analyte may be determined as an “on/off” or“normal/abnormal” situation. Detection of the analyte, for example, maybe indicative that insulin is needed; a trip to the doctor to checkcholesterol; ovulation is occurring; kidney dialysis is needed; druglevels are present (e.g., especially in the case of illegal drugs) ortoo high/too low (e.g., important in care of geriatrics in particular innursing homes). As another embodiment, however, an analyte may bedetermined quantitatively.

In some cases, fluids received from the subject, such as plasma orserum, will often contain various analytes within the body that areimportant for diagnostic purposes, for example, markers for variousdisease states, such as glucose (e.g., for diabetics); other exampleanalytes include ions such as sodium, potassium, chloride, calcium,magnesium, and/or bicarbonate (e.g., to determine dehydration); gasessuch as carbon dioxide or oxygen; H⁺ (i.e., pH); metabolites such asurea, blood urea nitrogen or creatinine; hormones such as estradiol,estrone, progesterone, progestin, testosterone, androstenedione, etc.(e.g., to determine pregnancy, illicit drug use, or the like); orcholesterol. Other examples include insulin, or hormone levels. Asdiscussed herein, certain embodiments of the present invention aregenerally directed at methods for receiving fluids from the body, andoptionally determining one or more analytes within the received fluid.Thus, in some embodiments, at least a portion of the fluid may bestored, and/or analyzed to determine one or more analytes, e.g., amarker for a disease state, or the like. The fluid received from theskin and/or beneath the skin may be subjected to such uses, and/or oneor more materials previously delivered to the skin may be subject tosuch uses.

Still other potentially suitable analytes include various pathogens suchas bacteria or viruses, and/or markers produced by such pathogens. Thus,in certain embodiments of the invention, as discussed below, one or moreanalytes may be determined in some fashion, which may be useful indetermining a past, present and/or future condition of the subject.

In one set of embodiments, the sensor may be a test strip, for example,test strips that can be obtained commercially. Examples of test stripsinclude, but are not limited to, glucose test strips, urine test strips,pregnancy test strips, or the like. A test strip will typically includea band, piece, or strip of paper or other material and contain one ormore regions able to determine an analyte, e.g., via binding of theanalyte to a diagnostic agent or a reaction entity able to interact withand/or associate with the analyte. For example, the test strip mayinclude various enzymes or antibodies, glucose oxidase and/orferricyanide, or the like. The test strip may be able to determine, forexample, glucose, cholesterol, creatinine, ketones, blood, protein,nitrite, pH, urobilinogen, bilirubin, leucocytes, luteinizing hormone,etc., depending on the type of test strip. The test strip may be used inany number of different ways. In some cases, a test strip may beobtained commercially and inserted into the device, e.g., before orafter withdrawing blood, interstitial fluid, or other fluids from asubject. At least a portion of the blood or other fluid may be exposedto the test strip to determine an analyte, e.g., in embodiments wherethe device uses the test strip as a sensor so that the device itselfdetermines the analyte. In some cases, the device may be sold with atest strip pre-loaded, or a user may need to insert a test strip in adevice (and optionally, withdraw and replace the test strip betweenuses). In certain cases, the test strip may form an integral part of thedevice that is not removable by a user. In some embodiments, afterexposure to the blood or other fluid received from the subject, the teststrip may be removed from the device and determined externally, e.g.,using other apparatuses able to determine the test strip, for example,commercially-available test strip readers.

As mentioned, in some aspects, the device may include channels such asmicrofluidic channels. In some cases, the microfluidic channels are influid communication with a flow activator that is used to deliver toand/or withdraw fluids from the skin and/or beneath the skin. Forexample, in one set of embodiments, the device may include a hypodermicneedle or other needle (e.g., one or more microneedles) that can beinserted into the skin, and fluid may be delivered into or through theskin via the needle and/or received from the skin via the needle. Thedevice may also include one or more microfluidic channels to containfluid for delivery to the needle, e.g., from a source of fluid, and/orto withdraw fluid received from the skin and/or beneath the skin, e.g.,for delivery to an analytical chamber within the device, to a reservoirfor later analysis, or the like.

In some cases, more than one chamber may be present within the device,and in some cases, some or all of the chambers may be in fluidiccommunication, e.g., via channels such as microfluidic channels. Invarious embodiments, a variety of chambers and/or channels may bepresent within the device, depending on the application. For example,the device may contain chambers for sensing an analyte, chambers forholding reagents, chambers for controlling temperature, chambers forcontrolling pH or other conditions, chambers for creating or bufferingpressure or vacuum, chambers for controlling or dampening fluid flow,mixing chambers, or the like.

Thus, in one set of embodiments, the device may include a microfluidicchannel. As used herein, “microfluidic,” “microscopic,” “microscale,”the “micro-” prefix (for example, as in “microchannel”), and the likegenerally refers to elements or articles having widths or diameters ofless than about 1 mm, and less than about 100 microns (micrometers) insome cases. In some embodiments, larger channels may be used instead of,or in conjunction with, microfluidic channels for any of the embodimentsdiscussed herein. For examples, channels having widths or diameters ofless than about 10 mm, less than about 9 mm, less than about 8 mm, lessthan about 7 mm, less than about 6 mm, less than about 5 mm, less thanabout 4 mm, less than about 3 mm, or less than about 2 mm may be used incertain instances. In some cases, the element or article includes achannel through which a fluid can flow. In all embodiments, specifiedwidths can be a smallest width (i.e. a width as specified where, at thatlocation, the article can have a larger width in a different dimension),or a largest width (i.e. where, at that location, the article has awidth that is no wider than as specified, but can have a length that isgreater). Thus, for instance, the microfluidic channel may have anaverage cross-sectional dimension (e.g., perpendicular to the directionof flow of fluid in the microfluidic channel) of less than about 1 mm,less than about 500 microns, less than about 300 microns, or less thanabout 100 microns. In some cases, the microfluidic channel may have anaverage diameter of less than about 60 microns, less than about 50microns, less than about 40 microns, less than about 30 microns, lessthan about 25 microns, less than about 10 microns, less than about 5microns, less than about 3 microns, or less than about 1 micron.

A “channel,” as used herein, means a feature on or in an article (e.g.,a substrate) that at least partially directs the flow of a fluid. Insome cases, the channel may be formed, at least in part, by a singlecomponent, e.g. an etched substrate or molded unit. The channel can haveany cross-sectional shape, for example, circular, oval, triangular,irregular, square or rectangular (having any aspect ratio), or the like,and can be covered or uncovered (i.e., open to the external environmentsurrounding the channel). In embodiments where the channel is completelycovered, at least one portion of the channel can have a cross-sectionthat is completely enclosed, and/or the entire channel may be completelyenclosed along its entire length with the exception of its inlet andoutlet.

A channel may have any aspect ratio (length to average cross-sectionaldimension), e.g., an aspect ratio of at least about 2:1, more typicallyat least about 3:1, at least about 5:1, at least about 10:1, etc. Asused herein, a “cross-sectional dimension,” in reference to a fluidic ormicrofluidic channel, is measured in a direction generally perpendicularto fluid flow within the channel. A channel generally will includecharacteristics that facilitate control over fluid transport, e.g.,structural characteristics and/or physical or chemical characteristics(hydrophobicity vs. hydrophilicity) and/or other characteristics thatcan exert a force (e.g., a containing force) on a fluid. The fluidwithin the channel may partially or completely fill the channel. In somecases the fluid may be held or confined within the channel or a portionof the channel in some fashion, for example, using surface tension(e.g., such that the fluid is held within the channel within a meniscus,such as a concave or convex meniscus). In an article or substrate, some(or all) of the channels may be of a particular size or less, forexample, having a largest dimension perpendicular to fluid flow of lessthan about 5 mm, less than about 2 mm, less than about 1 mm, less thanabout 500 microns, less than about 200 microns, less than about 100microns, less than about 60 microns, less than about 50 microns, lessthan about 40 microns, less than about 30 microns, less than about 25microns, less than about 10 microns, less than about 3 microns, lessthan about 1 micron, less than about 300 nm, less than about 100 nm,less than about 30 nm, or less than about 10 nm or less in some cases.In one embodiment, the channel is a capillary.

As mentioned, in accordance with some aspects, blood, plasma, serum,interstitial fluid, or other bodily fluids may be stored within thedevice for later use and/or analysis. For instance, the device mayinclude a storage chamber having an internal pressure less thanatmospheric or ambient pressure prior to receiving blood, plasma, serum,interstitial fluid, or other bodily fluids. In certain embodiments,relatively small storage chambers may be used, e.g., so that the devicemay have a relatively small size. For example, the storage chamber mayhave a volume of less than about 25 ml, less than about 20 ml, less thanabout 15 ml, less than about 10 ml, less than about 5 ml, less thanabout 3 ml, less than about 2 ml, or less than about 1 ml.

In one set of embodiments, the device may include an anticoagulant or astabilizing agent for stabilizing the fluid received from the skinand/or beneath the skin, e.g., within the storage chamber. For example,the fluid may be stored within the device for a certain period of time,and/or the device (or a portion thereof) may be moved or shipped toanother location for analysis or later use. For instance, a device maycontain anticoagulant or a stabilizing agent in a storage chamber. Insome cases, more than one anticoagulant may be used, e.g., in the samestorage chamber, or in more than one storage chamber.

The device may include an anticoagulant or a stabilizing agent forstabilizing the fluid received from the skin and/or beneath the skin. Asa specific non-limiting example, an anticoagulant may be used for bloodreceived from the skin. Examples of anticoagulants include, but are notlimited to, heparin, citrate, thrombin, oxalate,ethylenediaminetetraacetic acid (EDTA), sodium polyanethol sulfonate,acid citrate dextrose. Other agents may be used in conjunction with orinstead of anticoagulants, for example, stabilizing agents such assolvents, diluents, buffers, chelating agents, antioxidants, bindingagents, preservatives, antimicrobials, or the like. Examples ofpreservatives include, for example, benzalkonium chloride,chlorobutanol, parabens, or thimerosal. Non-limiting examples ofantioxidants include ascorbic acid, glutathione, lipoic acid, uric acid,carotenes, alpha-tocopherol, ubiquinol, or enzymes such as catalase,superoxide dismutase, or peroxidases. Examples of microbials include,but are not limited to, ethanol or isopropyl alcohol, azides, or thelike. Examples of chelating agents include, but are not limited to,ethylene glycol tetraacetic acid or ethylenediaminetetraacetic acid.Examples of buffers include phosphate buffers such as those known toordinary skill in the art.

In one set of embodiments, at least a portion of the device may becolored to indicate the anticoagulant(s) contained within the device. Insome cases, the colors used may be identical or equivalent to thatcommercially used for Vacutainers™, Vacuettes™, or othercommercially-available phlebotomy equipment. For example, lavenderand/or purple may indicate ethylenediaminetetraacetic acid, light bluemay indicate citrate, dark blue may indicate ethylenediaminetetraaceticacid, green may indicate heparin, gray may indicate a fluoride and/or anoxalate, orange may indicate a thrombin, yellow may indicate sodiumpolyanethol sulfonate and/or acid citrate dextrose, black may indicatecitrate, brown may indicate heparin, etc. In other embodiments, however,other coloring systems may be used.

Other coloring systems may be used in other embodiments of theinvention, not necessarily indicative of anti-coagulants. For example,in one set of embodiments, the device carries a color indicative of arecommended bodily use site for the device, e.g., a first colorindicative of a device suitable for placement on the back, a secondcolor indicative of a device suitable for placement on a leg, a thirdcolor indicative of a device suitable for placement on the arm, etc.

As mentioned, in one set of embodiments, a device of the invention asdiscussed herein may be shipped to another location for analysis. Insome cases, the device may include an anticoagulant or a stabilizingagent contained within the device, e.g., within a storage chamber forthe fluid. Thus, for example, fluid such as blood or interstitial fluidreceived from the skin and/or beneath the skin may be delivered to achamber (e.g., a storage chamber) within the device, then the device, ora portion of the device (e.g., a module) may be shipped to anotherlocation for analysis. Any form of shipping may be used, e.g., via mail.

In some embodiments, the device may be attached to a suitable externalapparatus able to analyze a portion of the device (e.g., containing afluid, such as blood, serum, or plasma), and/or the external apparatusmay remove at least some of the blood, plasma, serum, or other fluidfrom the device for subsequent analysis and/or storage. In some cases,however, at least some analysis may be performed by the device itself,e.g., using one or more sensors, etc., contained within the device. Insome cases, the chambers may be in fluidic communication with one ormore flow activators and/or one or more microfluidic channels. Forinstance, the device may contain a chamber for collecting fluid receivedfrom a subject (e.g., for storage and/or later analysis), a chamber forcontaining a fluid for delivery to the subject (e.g., blood, saline,optionally containing drugs, hormones, vitamins, pharmaceutical agents,or the like), etc.

For example, as discussed in detail below, in some cases, a storagechamber may contain a reagent or a reaction entity able to react with ananalyte suspected of being present in the blood (or other fluid, e.g.,plasma or serum) entering the device, and in some cases, the reactionentity may be determined to determine the analyte. In some cases, thedetermination may be made externally of the device, e.g., by determininga color change or a change in fluorescence, etc. The determination maybe made by a person, or by an external apparatus able to analyze atleast a portion of the device. In some cases, the determination may bemade without removing blood, serum, or plasma from the device, e.g.,from the storage chamber. (In other cases, however, blood or otherfluids may first be removed from the device before being analyzed.) Forexample, the device may include one or more sensors (e.g., ion sensorssuch as K⁺ sensors, colorimetric sensors, fluorescence sensors, etc.),and/or contain “windows” that allow light to penetrate the device. Thewindows may be formed of glass, plastic, etc., and may be selected to beat least partially transparent to one or a range of suitablewavelengths, depending on the analyte or condition to be determined. Asa specific example, the entire device (or a portion thereof) may bemounted in an external apparatus, and light from the external apparatusmay pass through or otherwise interact with at least a portion of thedevice (e.g., be reflected or refracted via the device) to determine theanalyte and/or the reaction entity.

After withdraw of the fluid into the device, the device, or a portionthereof, may be removed from the skin of the subject, e.g., by thesubject or by another person. For example, the entire device may beremoved, or a portion of the device containing the storage reservoir maybe removed from the device, and optionally replaced with another storagereservoir. Thus, for instance, in one embodiment, the device may containtwo or more modules, for example, a first module that is able to causereceiving of fluid from the skin into a storage reservoir, and a secondmodule containing the storage module. In some cases, the modulecontaining the storage reservoir may be removed from the device. Otherexamples of modules and modular systems are discussed herein; stillother examples are discussed in U.S. Provisional Patent Application Ser.No. 61/256,931, filed Oct. 30, 2009, entitled “Modular Systems forApplication to the Skin,” incorporated by reference herein in itsentirety.

The received fluid may then be sent to a clinical and/or laboratorysetting, e.g., for analysis. In some embodiments, the entire device maybe sent to the clinical and/or laboratory setting; in other embodiments,however, only a portion of the device (e.g., a module containing astorage reservoir containing the fluid) may be sent to the clinicaland/or laboratory setting. In some cases, the fluid may be shipped usingany suitable technique (e.g., by mail, by hand, etc.). In certaininstances, the subject may give the fluid to appropriate personnel at aclinical visit. For instance, a doctor may prescribe a device asdiscussed above for use by the subject, and at the next doctor visit,the subject may give the doctor the received fluid, e.g., containedwithin a device or module.

In one aspect, a subject having a condition such as a physiologicalcondition to be analyzed (or other user, such as medical personnel)reads and/or otherwise determines a signal from a device. For example,the device may transmit a signal indicative of a condition of thesubject and/or the device. Alternatively, or in addition, a signalproduced by a device can be acquired in the form of a representation(e.g. a digitized signal, or the like) and transmitted to another entityfor analysis and/or action. For example, a signal can be produced by adevice, e.g., based on a sensor reading of an analyte, based on fluiddelivered to and/or received from the skin and/or beneath the skin,based on a condition of the device, or the like. The signal mayrepresent any suitable data or image. For example, the signal mayrepresent the presence and/or concentration of an analyte in fluidreceived from a subject, the amount of fluid received from a subjectand/or delivered to the subject, the number of times the device has beenused, the battery life of the device, the amount of vacuum left in thedevice, the cleanliness or sterility of the device, the identity of thedevice (e.g., where multiple devices are given unique identificationnumbers, to prevent counterfeiting, accidental exchange of equipment toincorrect users, etc.), or the like. For instance, in one set ofembodiments, an image of the signal (e.g., a visual image or photograph)can be obtained and transmitted to a different entity (for example, auser can take a cell phone picture of a signal generated by the deviceand send it, via cell phone, the other entity).

The other entity that the signal is transmitted to can be a human (e.g.,a clinician) or a machine. In some cases, the other entity may be ableto analyze the signal and take appropriate action. In one arrangement,the other entity is a machine or processor that analyzes the signal andoptionally sends a signal back to the device to give direction as toactivity (e.g., a cell phone can be used to transmit an image of asignal to a processor which, under one set of conditions, transmits asignal back to the same cell phone giving direction to the user, ortakes other action). Other actions can include automatic stimulation ofthe device or a related device to dispense a medicament orpharmaceutical, or the like. The signal to direct dispensing of apharmaceutical can take place via the same used to transmit the signalto the entity (e.g., cell phone) or a different vehicle or pathway.Telephone transmission lines, wireless networks, Internet communication,and the like can also facilitate communication of this type.

As one specific example, a device may be a glucose monitor. A signal maybe generated by the device and an image of the signal captured by a cellphone camera and then transmitted via cell phone to a clinician. Theclinician may then determine that the glucose (or e.g., insulin) levelis appropriate or inappropriate and send a message indicating this backto the subject via cell phone.

Information regarding the analysis can also be transmitted to the sameor a different entity, or a different location simply by removing thedevice or a portion of the device from the skin of the subject andtransferring it to a different location. For example, a device can beused in connection with a subject to analyze presence and/or amount of aparticular analyte. At some point after the onset of use, the device, ora portion of the device carrying a signal or signals indicative of theanalysis or analyses, can be removed and, e.g., attached to a recordassociated with the subject. As a specific example, a patch or otherdevice can be worn by a subject to determine presence and/or amount ofone or more analytes qualitatively, quantitatively, and/or over time.The subject can visit a clinician who can remove the patch or a portionof the patch (or other device) and attach it to a medical recordassociated with the subject.

A variety of materials and methods, according to certain aspects of theinvention, can be used to form the device, e.g., microfluidic channels,chambers, etc. For example, various components of the invention can beformed from solid materials, in which the channels can be formed viamicromachining, film deposition processes such as spin coating andchemical vapor deposition, laser fabrication, photolithographictechniques, etching methods including wet chemical or plasma processes,and the like. See, for example, Scientific American, 248:44-55, 1983(Angell, et al).

In one set of embodiments, various components of the systems and devicesof the invention can be formed of a polymer, for example, an elastomericpolymer such as polydimethylsiloxane (“PDMS”), polytetrafluoroethylene(“PTFE” or Teflon®), or the like. For instance, according to oneembodiment, a microfluidic channel may be implemented by fabricating thefluidic system separately using PDMS or other soft lithographytechniques (details of soft lithography techniques suitable for thisembodiment are discussed in the references entitled “Soft Lithography,”by Younan Xia and George M. Whitesides, published in the Annual Reviewof Material Science, 1998, Vol. 28, pages 153-184, and “Soft Lithographyin Biology and Biochemistry,” by George M. Whitesides, Emanuele Ostuni,Shuichi Takayama, Xingyu Jiang and Donald E. Ingber, published in theAnnual Review of Biomedical Engineering, 2001, Vol. 3, pages 335-373;each of these references is incorporated herein by reference).

Other examples of potentially suitable polymers include, but are notlimited to, polyethylene terephthalate (PET), polyacrylate,polymethacrylate, polycarbonate, polystyrene, polyethylene,polypropylene, polyvinylchloride, cyclic olefin copolymer (COC),polytetrafluoroethylene, a fluorinated polymer, a silicone such aspolydimethylsiloxane, polyvinylidene chloride, bis-benzocyclobutene(“BCB”), a polyimide, a polyester, a fluorinated derivative of apolyimide, or the like. Another example is polyethylene terephthalateglycol (“PETG”). In PETG, the ethylene glycol group that is normallypart of the PET chain is partially substituted for cyclohexanedimethanol (e.g., approximately 15-35 mol % of the ethylene groups arereplaced), which may, in some cases, slow down the crystallization ofthe polymer when injection molded to allow better processing.Combinations, copolymers, derivatives, or blends involving polymersincluding those described above are also envisioned. The device may alsobe formed from composite materials, for example, a composite of apolymer and a semiconductor material.

In some embodiments, various components of the invention are fabricatedfrom polymeric and/or flexible and/or elastomeric materials, and can beconveniently formed of a hardenable fluid, facilitating fabrication viamolding (e.g. replica molding, injection molding, cast molding, etc.).The hardenable fluid can be essentially any fluid that can be induced tosolidify, or that spontaneously solidifies, into a solid capable ofcontaining and/or transporting fluids contemplated for use in and withthe fluidic network. In one embodiment, the hardenable fluid comprises apolymeric liquid or a liquid polymeric precursor (i.e. a “prepolymer”).Suitable polymeric liquids can include, for example, thermoplasticpolymers, thermoset polymers, waxes, metals, or mixtures or compositesthereof heated above their melting point. As another example, a suitablepolymeric liquid may include a solution of one or more polymers in asuitable solvent, which solution forms a solid polymeric material uponremoval of the solvent, for example, by evaporation. Such polymericmaterials, which can be solidified from, for example, a melt state or bysolvent evaporation, are well known to those of ordinary skill in theart. A variety of polymeric materials, many of which are elastomeric,are suitable, and are also suitable for forming molds or mold masters,for embodiments where one or both of the mold masters is composed of anelastomeric material. A non-limiting list of examples of such polymersincludes polymers of the general classes of silicone polymers, epoxypolymers, and acrylate polymers. Epoxy polymers are characterized by thepresence of a three-membered cyclic ether group commonly referred to asan epoxy group, 1,2-epoxide, or oxirane. For example, diglycidyl ethersof bisphenol A can be used, in addition to compounds based on aromaticamine, triazine, and cycloaliphatic backbones. Another example includesthe well-known Novolac polymers. Non-limiting examples of siliconeelastomers suitable for use according to the invention include thoseformed from precursors including the chlorosilanes such asmethylchlorosilanes, ethylchlorosilanes, phenylchlorosilanes, etc.

Silicone polymers are used in certain embodiments, for example, thesilicone elastomer polydimethylsiloxane. Non-limiting examples of PDMSpolymers include those sold under the trademark Sylgard by Dow ChemicalCo., Midland, Mich., and particularly Sylgard 182, Sylgard 184, andSylgard 186. Silicone polymers including PDMS have several beneficialproperties simplifying fabrication of the microfluidic structures of theinvention. For instance, such materials are inexpensive, readilyavailable, and can be solidified from a prepolymeric liquid via curingwith heat. For example, PDMSs are typically curable by exposure of theprepolymeric liquid to temperatures of about, for example, about 65° C.to about 75° C. for exposure times of, for example, about an hour. Also,silicone polymers, such as PDMS, can be elastomeric and thus may beuseful for forming very small features with relatively high aspectratios, necessary in certain embodiments of the invention. Flexible(e.g., elastomeric) molds or masters can be advantageous in this regard.

One advantage of forming structures such as microfluidic structures ofthe invention from silicone polymers, such as PDMS, is the ability ofsuch polymers to be oxidized, for example by exposure to anoxygen-containing plasma such as an air plasma, so that the oxidizedstructures contain, at their surface, chemical groups capable ofcross-linking to other oxidized silicone polymer surfaces or to theoxidized surfaces of a variety of other polymeric and non-polymericmaterials. Thus, components can be fabricated and then oxidized andessentially irreversibly sealed to other silicone polymer surfaces, orto the surfaces of other substrates reactive with the oxidized siliconepolymer surfaces, without the need for separate adhesives or othersealing means. In most cases, sealing can be completed simply bycontacting an oxidized silicone surface to another surface without theneed to apply auxiliary pressure to form the seal. That is, thepre-oxidized silicone surface acts as a contact adhesive againstsuitable mating surfaces. Specifically, in addition to beingirreversibly sealable to itself, oxidized silicone such as oxidized PDMScan also be sealed irreversibly to a range of oxidized materials otherthan itself including, for example, glass, silicon, silicon oxide,quartz, silicon nitride, polyethylene, polystyrene, glassy carbon, andepoxy polymers, which have been oxidized in a similar fashion to thePDMS surface (for example, via exposure to an oxygen-containing plasma).Oxidation and sealing methods useful in the context of the presentinvention, as well as overall molding techniques, are described in theart, for example, in an article entitled “Rapid Prototyping ofMicrofluidic Systems and Polydimethylsiloxane,” Anal. Chem., 70:474-480,1998 (Duffy et al.), incorporated herein by reference.

Another advantage to forming microfluidic structures of the invention(or interior, fluid-contacting surfaces) from oxidized silicone polymersis that these surfaces can be much more hydrophilic than the surfaces oftypical elastomeric polymers (where a hydrophilic interior surface isdesired). Such hydrophilic channel surfaces can thus be more easilyfilled and wetted with aqueous solutions than can structures comprisedof typical, unoxidized elastomeric polymers or other hydrophobicmaterials.

In another aspect, the present invention is directed to a kit includingone or more of the compositions previously discussed, e.g., a kitincluding a device for the delivery to and/or receiving of fluid fromthe skin and/or beneath the skin, a kit including a device able tocreate a pooled region of fluid within the skin of a subject, a kitincluding a device able to determine a fluid, or the like. A “kit,” asused herein, typically defines a package or an assembly including one ormore of the compositions or devices of the invention, and/or othercompositions or devices associated with the invention, for example, aspreviously described. For example, in one set of embodiments, the kitmay include a device and one or more compositions for use with thedevice. Each of the compositions of the kit, if present, may be providedin liquid form (e.g., in solution), or in solid form (e.g., a driedpowder). In certain cases, some of the compositions may be constitutableor otherwise processable (e.g., to an active form), for example, by theaddition of a suitable solvent or other species, which may or may not beprovided with the kit. Examples of other compositions or componentsassociated with the invention include, but are not limited to, solvents,surfactants, diluents, salts, buffers, emulsifiers, chelating agents,fillers, antioxidants, binding agents, bulking agents, preservatives,drying agents, antimicrobials, needles, syringes, packaging materials,tubes, bottles, flasks, beakers, dishes, frits, filters, rings, clamps,wraps, patches, containers, tapes, adhesives, and the like, for example,for using, administering, modifying, assembling, storing, packaging,preparing, mixing, diluting, and/or preserving the compositionscomponents for a particular use, for example, to a sample and/or asubject.

A kit of the invention may, in some cases, include instructions in anyform that are provided in connection with the compositions of theinvention in such a manner that one of ordinary skill in the art wouldrecognize that the instructions are to be associated with thecompositions of the invention. For instance, the instructions mayinclude instructions for the use, modification, mixing, diluting,preserving, administering, assembly, storage, packaging, and/orpreparation of the compositions and/or other compositions associatedwith the kit. In some cases, the instructions may also includeinstructions for the delivery and/or administration of the compositions,for example, for a particular use, e.g., to a sample and/or a subject.The instructions may be provided in any form recognizable by one ofordinary skill in the art as a suitable vehicle for containing suchinstructions, for example, written or published, verbal, audible (e.g.,telephonic), digital, optical, visual (e.g., videotape, DVD, etc.) orelectronic communications (including Internet or web-basedcommunications), provided in any manner.

In some embodiments, the present invention is directed to methods ofpromoting one or more embodiments of the invention as discussed herein.As used herein, “promoted” includes all methods of doing businessincluding, but not limited to, methods of selling, advertising,assigning, licensing, contracting, instructing, educating, researching,importing, exporting, negotiating, financing, loaning, trading, vending,reselling, distributing, repairing, replacing, insuring, suing,patenting, or the like that are associated with the systems, devices,apparatuses, articles, methods, compositions, kits, etc. of theinvention as discussed herein. Methods of promotion can be performed byany party including, but not limited to, personal parties, businesses(public or private), partnerships, corporations, trusts, contractual orsub-contractual agencies, educational institutions such as colleges anduniversities, research institutions, hospitals or other clinicalinstitutions, governmental agencies, etc. Promotional activities mayinclude communications of any form (e.g., written, oral, and/orelectronic communications, such as, but not limited to, e-mail,telephonic, Internet, Web-based, etc.) that are clearly associated withthe invention.

In one set of embodiments, the method of promotion may involve one ormore instructions. As used herein, “instructions” can define a componentof instructional utility (e.g., directions, guides, warnings, labels,notes, FAQs or “frequently asked questions,” etc.), and typicallyinvolve written instructions on or associated with the invention and/orwith the packaging of the invention. Instructions can also includeinstructional communications in any form (e.g., oral, electronic,audible, digital, optical, visual, etc.), provided in any manner suchthat a user will clearly recognize that the instructions are to beassociated with the invention, e.g., as discussed herein.

The following documents are incorporated herein by reference: U.S.patent application Ser. No. 12/478,756, filed Jun. 4, 2009, entitled“Compositions and Methods for Diagnostics, Therapies, and OtherApplications,” by Levinson, published as U.S. Pat. Apl. Pub. No.2010/0069726 on Mar. 18, 2010; U.S. patent application Ser. No.12/716,222, filed Mar. 2, 2010, entitled “Oxygen Sensor,” by Levinson,et al., published as U.S. Pat. Apl. Pub. No. 2010/0249560 on Sep. 30,2010; U.S. patent application Ser. No. 12/716,233, filed Mar. 2, 2010,entitled “Systems and Methods for Creating and Using Suction Blisters orOther Pooled Regions of Fluid within the Skin,” by Levinson, et al.,published as U.S. Pat. Apl. Pub. No. 2011/0009847 on Jan. 13, 2011; U.S.patent application Ser. No. 12/716,226, filed Mar. 2, 2010, entitled“Techniques and Devices Associated with Blood Sampling,” by Levinson, etal., published as U.S. Pat. Apl. Pub. No. 2010/0256524 on Oct. 7, 2010;U.S. patent application Ser. No. 12/716,229, filed Mar. 2, 2010,entitled “Devices and Techniques Associated with Diagnostics, Therapies,and Other Applications, Including Skin-Associated Applications,” byBernstein, et al., published as U.S. Pat. Apl. Pub. No. 2010/0256465 onOct. 7, 2010; U.S. patent application Ser. No. 12/953,744, filed Nov.24, 2010, entitled “Patient-Enacted Sampling Technique,” by Levinson, etal.; U.S. patent application Ser. No. 12/915,735, filed Oct. 29, 2010,entitled “Systems and Methods for Application to Skin and Control ofActuation, Delivery, and/or Perception Thereof,” by Chickering, et al.;U.S. patent application Ser. No. 12/915,789, filed Oct. 29, 2010,entitled “Systems and Methods for Treating, Sanitizing, and/or Shieldingthe Skin or Devices Applied to the Skin,” by Bernstein, et al.; U.S.patent application Ser. No. 12/915,820, filed Oct. 29, 2010, entitled“Relatively Small Devices Applied to the Skin, Modular Systems, andMethods of Use Thereof,” by Bernstein, et al.; U.S. patent applicationSer. No. 13/006,177, filed Jan. 13, 2011, entitled “Rapid Deliveryand/or Withdrawal of Fluids,” by Chickering, et al.; U.S. patentapplication Ser. No. 13/006,165, filed Jan. 13, 2011, entitled “SamplingDevice Interfaces,” by Chickering, et al.; U.S. Prov. Pat. Apl. Ser. No.61/357,582, filed Jun. 23, 2010, entitled “Sampling Devices and MethodsInvolving Relatively Little Pain,” by Chickering, et al.; U.S. Prov.Pat. Apl. Ser. No. 61/367,607, filed Jul. 26, 2010, entitled “RapidDelivery and/or Withdrawal of Fluids,” by Davis, et al.; U.S. Prov. Pat.Apl. Ser. No. 61/373,764, filed Aug. 13, 2010, entitled “Clinical and/orConsumer Techniques and Devices,” by Chickering, et al.; and U.S. Prov.Pat. Apl. Ser. No. 61/411,566, filed Nov. 9, 2010, entitled “Systems andInterfaces for Blood Sampling,” by Brancazio, et al.

Also incorporated herein by reference in their entireties are U.S.Provisional Patent Application Ser. No. 61/480,977, entitled “Deliveringand/or Receiving Fluids,” by Gonzales-Zugasti, et al., and U.S.Provisional Patent Application Ser. No. 61/480,960, entitled “Methodsand Devices for Withdrawing Fluids from a Subject Using ReducedPressure,” by Haghgooie, et al., each filed on Apr. 29, 2011. Alsoincorporated herein by reference in their entireties are U.S. andinternational patent applications each entitled “Delivering and/orReceiving Fluids,” and U.S. and international patent applications eachentitled “Methods and Devices for Withdrawing Fluids from a SubjectUsing Reduced Pressure,” each of which is filed on even date herewith.In addition, U.S. Provisional Patent Application Ser. No. 61/480,941,filed Apr. 29, 2011, entitled “Plasma or Serum Production and Removal ofFluids under Reduced Pressure,” by Haghgooie, et al., and U.S.Provisional Patent Application Ser. No. 61/549,437, filed Oct. 20, 2011,entitled “Systems and Methods for Collection and/or Manipulation ofBlood Spots or Other Bodily Fluids,” by Bernstein, et al. are eachincorporated herein by reference in its entirety.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of the present invention.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

What is claimed is:
 1. A device for receiving blood from a subject andprocessing the blood to form plasma or serum, the device comprising: aninlet for introduction of blood from the subject into the device; astorage chamber for receiving plasma or serum; a membrane that issubstantially impermeable to cells, wherein the membrane separates theinlet from the storage chamber and is capable of separating bloodpassing through to produce a portion enriched in plasma or serum; and avacuum chamber, separate from the storage chamber, having a pressureless than ambient pressure; wherein the device further comprises a firstmodule and a second module removable from the first module, wherein thesecond module comprises the storage chamber.
 2. The device of claim 1,wherein the storage chamber has a volume of less than about 10 ml. 3.The device of claim 1, wherein at least a portion of the storage chamberis coated with a material that promotes thrombolysis.
 4. The device ofclaim 1, wherein at least a portion of the storage chamber is coatedwith a polyester.
 5. The device of claim 1, wherein the device furthercontains an anticoagulant.
 6. The device of claim 5, wherein theanticoagulant comprises heparin.
 7. The device of claim 5, wherein theanticoagulant includes one or more of citrate, thrombin, oxalate,ethylenediaminetetraacetic acid (EDTA), sodium polyanethol sulfonate, oracid citrate dextrose.
 8. The device of claim 1, wherein the membrane isa separation membrane.
 9. The device of claim 1, wherein the membranecomprises a copolymer.
 10. The device of claim 1, wherein the membranehas an average pore diameter of less than about 20 micrometers.
 11. Thedevice of claim 1, wherein the inlet is in fluid communication with themembrane by the fluid communication pathway.
 12. The device of claim 1,wherein the inlet is in fluid communication with the membrane by amicrofluidic channel.
 13. The device of claim 1, wherein the vacuumchamber has a pressure, prior to introduction of a bodily fluid from thesubject into the device, that is less than about 100 mmHg below ambientpressure.
 14. The device of claim 1, further comprising a septum influid communication with the storage chamber.
 15. The device of claim14, wherein the septum comprises silicone.
 16. The device of claim 1,wherein the device further comprises one or more microneedles positionedto be insertable into the skin of the subject to cause blood to flow tothe inlet.
 17. The device of claim 16, further comprising an activatorthat, when activated, fluidly communicates the pressure from the vacuumchamber to the one or more microneedles, wherein prior to activating theactivator, the pressure from the vacuum chamber is not in fluidcommunication with the one or more microneedles.
 18. The device of claim1, further comprising a seal that can be manipulated to control a fluidcommunication pathway between the vacuum chamber and the storagechamber.
 19. The device of claim 1, wherein the device further comprisesa second membrane that is gas permeable but is substantially liquidimpermeable, separating the storage chamber from the vacuum chamber. 20.The device of claim 1, wherein the device is self-contained.
 21. Adevice for receiving blood from a subject and processing the blood toform plasma or serum, the device comprising: an inlet for introductionof a bodily fluid from the subject into the device; a storage chamberfor receiving plasma or serum; a first membrane that is substantiallyimpermeable to cells, wherein the first membrane separates the inletfrom the storage chamber and is capable of separating blood passingthrough to produce a portion enriched in plasma or serum; a vacuumchamber, separate from the storage chamber, having a pressure less thanambient pressure; and a second membrane that is gas permeable but issubstantially liquid impermeable, wherein the second membrane separatesthe storage chamber from the vacuum chamber.
 22. The device of claim 21,wherein the device further comprises a first module and a second moduleremovable from the first module, wherein the second module comprises thestorage chamber.
 23. The device of claim 21, wherein the device furthercontains an anticoagulant.
 24. The device of claim 21, wherein thevacuum chamber has a pressure, prior to introduction of a bodily fluidfrom the subject into the device, that is less than about 100 mmHg belowambient pressure.
 25. The device of claim 21, wherein the storagechamber has a volume of less than about 10 ml.
 26. The device of claim21, wherein the device further comprises one or more microneedlespositioned to be insertable into the skin of the subject to cause bloodto flow to the inlet.
 27. The device of claim 26, further comprising anactivator that, when activated, fluidly communicates the pressure fromthe vacuum chamber to the one or more microneedles, wherein prior toactivating the activator, the pressure from the vacuum chamber is not influid communication with the one or more microneedles.
 28. The device ofclaim 21, further comprising a seal that can be manipulated to control afluid communication pathway between the vacuum chamber and the storagechamber.